Great explanation, but the short stem designed for the 44mm offset may have been why it was twitchy on the descents. The proper length stem would put your handlebars positioned correctly forward and over top of the the front hub. I have a Stumpy with 51MM offset and a 75mm stem. It is really stable on descents. My trails actually suit the more nimble handling of 51mm with the 29er wheels.
I've built a couple bikes with reduced offset forks and won't go back to 51mm. First thing I noticed was the lack of corrections I had to make in corners and how it just smoothed the steering out. My current 29" trail bike has 120/100mm travel with a 66* HTA and 40mm offset fork.
Good explanation. I went back and forth between a Giant Trance 29 with short offset and GT Sensor with slacker HA and regular offset. I found it virtually impossible to distinguish - the only handling difference I thought I felt was liking the shorter offset better for tight, twisting climbs... puzzling and certainly not worth all the BS.
Excellent video!!! Finding fork offset to also be a subtle change. Find it interesting that it's enough to truly alter the ride quality. First taste was a 2016 Specialized Stumjumper w/ a 46mm offset. Upgraded the fork to a 2018 wl a 51mm and the bike felt amazing; like the newly released 2019 model. I ride slow-speed technical trail up/down. Again, excellent video!!!
Awesome vid. I've watched a few vids now on offset, as I'm looking at changing out my fork, and hands down this is the best and easiest to understand explanation. Wish I found your channel first. You won a subscriber, thanks again.
Very good review, thank you for taking the time to dive into all the details and for providing your opinion on pros/cons. This is going to be helpful in the process of picking replacement fork for my short travel 29er 😁
After reading articles/watching videos for weeks this is the first video that makes it really clear - not just the technical stuff about trail etc but how it actually affects your riding - and how it relates to stem length and bar width. Thnx guys!
Best explanation on fork offset. I have the Blur also and have tried the different offsets but in 100mm Fox SC, at the time I wanted and incredibly fast handling bike. Fast forward 12 months and I have been getting stuck into Enduro and have just ordered a new Fox 34 in 44mm offset. It seems I don't like the twitchy bikes anymore.
Yay! I finally found the video I've been looking for. I just put the RS-1 with 51mm offset on my new Yeti SB100. I'm sure I got the right offset for my riding now.
nice work, mate. i have 2 bikes - the burly MegaTrail with a slackety-slack 64° hta, so running a Lyrik Ultimate with a crazy tight 37mm offset. it goes down hills like a champ! the other is a Spot Ryve 115, at 67.2° and running a fox 32 with 44mm offset. i find that on my Spot, a longer offset (51mm) is very twitchy on slow, tight corners. and less stable at high speeds. i then ran a 44mm offset, and the cornering at low speeds is more reliable. high speed control also improved. that being said, both bikes have the same anvl 32mm stem and 740mm wide bars. the odd thing, to me, is that subjectively the 51mm offset on the Ryve should help with slow speed cornering/climbing, but i dont see it. the high speed control on this bike is vastly improved, tho, as i have noticed. my overall claim is for me, 51mm offset on a steep HTA does not work well with a very short stem. YMMV
Great informative video. But I wish this bike was ridden and tested as a dedicated xc bike which it is and not a 3/4 trail bike. Everybody talks about how it descends but I haven't seen a single video on how it climbs tight steep switchbacks or technical climbing features.
Hey Marek! Thanks for watching and for your feedback - it's much appreciated! As I mentioned in the full review, I actually tested the Blur as a full-blown XC bike last year; singletrackworld.com/2018/03/first-ride-review-santa-cruz-blur-3-cc-xx1-reserve/ In answer to your comment, it does climb exceptionally well. It has a very stiff frame and the suspension is totally efficient even with the shock set wide open. The handling uphills is quite neutral and steady, and because the head tube is very short (90mm), it's possible to set it up with a very low bar height for maximum climbing power and efficiency. Following that original test, I requested a frameset on its own from Santa Cruz, with the idea of building it up as a custom bike. I wanted to try it out with a 120mm travel fork and some burlier tyres, mostly to see just how far it could be pushed. Turned out to be a really fun bike too! I'm actually turning it back into full-blown XC mode right now. Fox is sending me one of the new 32 Step-Cast forks with 100mm travel, and Hunt Bike Wheels has sent out some prototype XC racing wheels that I'll be able to talk about more soon. I've also just fitted a new longer/narrower cockpit setup, so it should end up being quite a sharper racer when those changes have been made. Hope that info helps explain, but if you've got any specific questions for me about the Blur as an XC bike, by all means send them through mate! [ST Wil]
I have an epic evo w a 42mm offset fork and a stumpjumper evo 29 with a 51mm offset and the stumpy steers better with a 63.5 HTA. I'll be swapping the epic to a 51 soon. It makes it handle like a bus in singletrack
Excellent information. So to clarify and check if you still feel the same a year later, you've no handling issues riding a evo 29 with 51mm offset, although a complete bike is spec'ed with a 44mm offset? Did you get a chance to ride the evo with 44mm offset? I'm trying to decided if I use a fork I already have (51mm offset) on a new evo 29 frame I purchased, or look for a 44/42mm offset fork. Thanks!
Jesper Lund , that Ripley looks really fun! I think the Ripley is more of a trail bike without any apologies about it. The Blur trail is a XC bike with a party attitude, right? I just bought a Blur trail because where I live I have a lot of smooth single track that I ride all the time and then occasionally I’ll go ride chunky stuff or desert riding is only a couple hours a way. Plus I do a couple xc races every summer.
For an average rider, i'd say this offset thing 44 vs 51mm is pretty much bs. I personally went from a 51 to a 44 this season, no difference whatsoever. Why does everything have to be made so complicated? It just confuses people. Folks, don't think about this, just buy what is available atm of purchase if you are an average guy or gal just riding trails to stay in shape. More advanced riders can probably tell a difference no doubt.
I'm trying to work this offset out as my mate has fox 38s the grip 2 type I just got the fit4 38s on my new bike came with them but his has a sticker saying 27.5/29in below the wiper on the right fork mine don't and I'm running 27.5s his offset is ment to be 44 to 51 mine is 37 to 44 both being 44mm would I be able to run a 29 on the front or not they look no different side by side so he's coming over tomorrow gonna test this out! I mean my 27.5 look huge I don't see how the 29s would benefit me I'd never get on the bike! Just you seem to have more experience here it seems can you shed some light on this for me please?
@@Emtbtoday I wouldn't worry about the offset, especially if you're a pretty average rider. Your friends fork is a 29in fork, but you can put 27.5's on it if you want to. Yours is probably a 27.5 fork but go ahead and try his bigger wheel on it, you'll see instantly if it's a 27.5 fork.
Amazing video. Seems like the offset is not that important for amateurs, specially if you consider that the 51mm suspension sometimes is U$300 cheaper than the 44mm.
Great video, thanks for taking the time to really analyze how the changes to offset actually effected your ride out on the trail. Question: What I have yet to figure out is...slacker head angles were/are used to make bikes better at descending, so why did companies not just continue to make bikes slacker and not mess with offset? Or conversely, if offset has the same effect as slacking the head angle, why did the bike companies spend the last 5+ years remaking their bikes to make their frames slacker, when simply changing to a reduced offset fork would have the same effect? What am I missing? Do offset changes not have the same "effect" as head angle changes? Can I pickup a used frame with an "out-of-date" head angle of 69 degrees and slap a reduced offset fork on there to get the same ride characteristics of newer models?
Although trail is the most important part of steering geometry there are other factors that affect how the bike feels. Wheel flop is one, and touring bikes often achieve the desired trail with slightly steeper head angles and shorter offsets to reduce flop a bit because you may be using front panniers. On a mountain bike I think a slack head may also be desirable because of the angle at which you're hitting rocks and things with the front wheel. So it might be better to go even slacker and add offset... Not sure at what point excessive wheel flop becomes a problem. The other reason you need to go slacker than before is longer fork travel. An HT that's 65deg with a 140mm fork at 25% compression will be about 71 deg at full compression.
Besides what Ben C mentions, a slacker head angle increases the front centre, while a shorter offset reduces front-centre length (both increasing trail). Slacker indeed means a more beneficial angle for the fork to absorb impacts and less over the bars risk, a shorter offset might keep more weight on the front compared to a bike with the same trail with a slacker head angle.
Would be interesting to see the difference with different stems and frame sizes. So you could have the same seating position with different frame size and different stem lenght. I mean a small frame, 50mm stem and huge offset. Compare to medium frame, 30mm stem and short offset.
Does offset change how the bike handle steep sections? The difference between the two options with Rockshox is almost 10mm, you say that it shorter offset makes it more stable at speed but having the front wheel 10mm further out in front of you and also increasing the wheel base by 10mm not do anything for stability?
Nice information. Currently I have an Specialized Fuse Comp with a 120mm fork 51offset. I’m planning upgrading the fork to a 130mm or 140mm. Would be wise to reduce the offset to 44 or 42?
Glad you found it useful Roig! That's an interesting question you have on your Specialized Fuse hardtail. Firstly, do you know if the frame warranty will be voided if you put on a longer fork? Generally most frames will have a limit as to how long of a fork you can put on there, so you'll want to check that out first before assuming you can go much longer on travel. If you do end up going to a 130/140mm travel fork, remember that you'll be slackening out the head angle, as well as slackening the seat tube angle and lifting the BB height. So bear in mind the affect that will have on your riding position. Assuming you stick with a 51mm offset, that slacker head angle will still increase the trail figure. This will steady the steering behaviour a little bit. However, going to a 42/44mm offset will take that stability even further. A couple of questions to ask yourself; - What stem length are you using at the moment? And if you went to a reduced offset fork, could you comfortably go a bit shorter on the stem length? Or is the cockpit already a bit cramped? - How twitchy is the handling at the moment? Do you want to slow down the steering and improve straight-line tracking on the descents? The cockpit question is an important one, because bar width and stem length play an important role in determining how much leverage you have over the front wheel. In my experience, a reduced offset fork plays best with wide bars and a short stem. But if your frame is already a bit short on the top tube, going to a wider bar/shorter stem may not be ideal. Hope that helps mate! [ST Wil]
Singletrack Magazine Thanks a lot. The stock stem was 50mm I change to a 45mm. And the stock bar was 750mm, currently have a 760mm. The Fuse BB height is very low with the stock tires 3.0 Now I have 2.8 rear and 3.0 front. If I change the fork I will go 2.8 front and rear to compensate. Thanks for you time.
And to read all about the results of the fork offset test, check it out here: singletrackworld.com/2019/05/short-vs-long-fork-offset-testing-on-the-santa-cruz-blur/
Can anyone help me, I have a new specialized chisel and can upgrade the fork to a fox rhythm float 32 100m with a 51 offset! Will the be a plus or a negative as an upgrade
Please try 68.5 head angle/51 mm rake (very nervous at slow speed and steep curvy hills) and 69.5 angle/xx rake meaning the same trail (100 mm travel both), thank you!
I am suprised that Santa Cruz doesn't offer a 120mm for in their Blur build kits. Have you heard if this is possible in the future? I am eyeing a new Blur Tr in the next few years, but would rather have the 120mm fork and not the 110mm I believe?? Thanks
Any plans to test angled headsets on this bike? With 120 mm forks looking at 66 degrees? Would be interesting ro know how capable you could make it. Would also be good to test efficiency loss on climbs.
Hi, I have a SC Highball with 100mm 32 Stepcast fork, looking to upgrade it to a 120mm 34 Stepcast , what offset do you recommend and do you know how much this would shorten the reach by and how slack the head tube angle would be ? Thanks btw great video
I hv a 27.5 160mm fork with a 42mm offset with a 66 deg head angle on a 150 travel bike. I still crash alot. But it does feel more stable going fast thn going slow. Maybe thts y i crash alot (besides crappy skills). Bike makes u want to go faster all the time.
what if I'm looking to downsize the fork in general? I have looked at the geo the bike stock comes with a 44mm offset. The ht angle will be changing by +1 deg . so for this example would you stay with the spec'd 44mm offset or get a 51mm?
What about the specialized tires?? Which section did you tested? I'm looking for something grippy whith low rolling for my tallboy.......i know i'm out of topic, but, if you can tell me something.....
I ve a really weird experience. I ve two nomads. One in small, the other medium size. The 46mm offset doesn t feel good with the small frame. The bike is far too agressive in the turns. The medium is much more calm with the 46mm offset and still alive. Now i m very confused. I m thinking to buy a shorter offset for the small frame, to bring back some stability. But the wheelbase is shortening then, too. I don t know what effect this is going to have? On 29" forks the difference is 5mm and not a huge difference. On 27.5" it is 9mm difference which is plenty.
I'm currently using a 35mm stem with a 42mm offset fork and the handling seems a little bit twitchy. would matching the stem length to the offset help with this? say 40-45mm?
Great job. How do you predict size of bike comes into play? If I've got a XL bike with a big wheelbase...and the chainstay length is the same for all sizes...meaning that the front and center is growing disproportionately as you go up in size ....wouldn't i benefit from a 44mm offset and a 32mm i9 stem? 😊😷
Hi guys, question fo you guys, I'm thinking about getting a custom build on the " Yeti SB 130 turq frame & it's a particular question on the fork offset as you know Fox 36 fit 4 has 44 fork offset, but I would like to put a Rockshox Lyric but this has a 42 will this make the steering more stable on the downs ? But going up how will it affect the climbing ? Kind regards Drew
Yo Johannes! Apologies if there was any confusion there for ya - the offset is the measurement of how far forward the hub axle sits in front of the steering axis. This offset can be found in both the crown and the dropouts, though the most important aspect is the total amount of offset. Hope that helps explain, but if you've got any more questions, just shoot them through mate! [ST Wil]
Will gives a detailed explanation of both types of offset (crown and dropout) in Part one of this feature here :-) singletrackworld.com/2019/04/what-is-fork-offset-and-why-does-it-matter/ [ST Mark]
The difference in axle to crown measurement between a 170mm single crown fork and a 200mm dual crown fork is about 15mm so the difference isn't that major. There will be less than a 1° change in head angle/ seat angle. You'll lift the bottom bracket by roughly 6mm and lose 8mm roughly of reach. If that along with more stiffness and travel up front is what you want then go for it. It will probably void the frame warrantee if you have one because the dual crown will put more stress on the head tube due to more stiffness and longer axle to crown
Yo Eskohl! In most forks, the total amount of offset is made up of both the lowers and the crown. However, if you buy a 44mm or a 51mm offset fork, both with have identical lowers - the difference between the two is entirely in the crown. [ST Wil]
I think u have it wrong . Longer offset means greater caster means more nimble and lighter with the steering. 44 should give u less caster if anything but then I doubt we could feel 5 mm difference in offset.
Shorter offset moves the wheel backwards and therefore trails further behind the steering axis. This leads to more stability. Think of it like caster wheels on a shopping trolley, the further back they would sit, the more stable they will be
Actually, you are wrong in one thing. More trail = better stability AT HIGH SPEEDS, less stability AT LOW SPEEDS. Bike becomes unstable, harder to ride without hands with less offset=more trail.
Nice clear explanation, without over complicating it.
Cheers Ruben - glad you liked it, and appreciate the feedback!
[ST Wil]
@@singletrackThis helped me confirm that I should buy a 51mm offset when upgrading from my RS Recon to Marz Bomber !
I've been looking at fork offset articles and videos for weeks and I think this is the best explanation yet!
Best explanation I've found on fork offset! Thank you, well done.
I found going from a 35mm to a 50mm stem calmed down the high speed twitch on a 51mm fork.
Best explanation on fork offset without sitting on the fence about the difference. Thank you!!!!
Great explanation, but the short stem designed for the 44mm offset may have been why it was twitchy on the descents. The proper length stem would put your handlebars positioned correctly forward and over top of the the front hub. I have a Stumpy with 51MM offset and a 75mm stem. It is really stable on descents. My trails actually suit the more nimble handling of 51mm with the 29er wheels.
Best explanation I've seen yet. Great job
I've built a couple bikes with reduced offset forks and won't go back to 51mm. First thing I noticed was the lack of corrections I had to make in corners and how it just smoothed the steering out. My current 29" trail bike has 120/100mm travel with a 66* HTA and 40mm offset fork.
Finally 44mm vs 51mm offset doubts cleared, thanks
Great video and explanation. Fast becoming a go to channel for me. Really relatable advice and info
Awesome to hear Tyler, and glad you enjoyed the video!
[ST Wil]
brilliant explanation without any of the nonsense "banter", well done, new subscriber!
Good explanation. I went back and forth between a Giant Trance 29 with short offset and GT Sensor with slacker HA and regular offset. I found it virtually impossible to distinguish - the only handling difference I thought I felt was liking the shorter offset better for tight, twisting climbs... puzzling and certainly not worth all the BS.
Perfectly clear and to the point.
That’s was an outstanding explanation of fork offset characteristics. 👍🏼
This is by far the most comprehensive and clear explanation/opinion on fork offset. Thanks!
Finally someone who can explain it 👍🏽
Excellent video!!! Finding fork offset to also be a subtle change. Find it interesting that it's enough to truly alter the ride quality. First taste was a 2016 Specialized Stumjumper w/ a 46mm offset. Upgraded the fork to a 2018 wl a 51mm and the bike felt amazing; like the newly released 2019 model. I ride slow-speed technical trail up/down. Again, excellent video!!!
Awesome vid. I've watched a few vids now on offset, as I'm looking at changing out my fork, and hands down this is the best and easiest to understand explanation. Wish I found your channel first.
You won a subscriber, thanks again.
Very good review, thank you for taking the time to dive into all the details and for providing your opinion on pros/cons.
This is going to be helpful in the process of picking replacement fork for my short travel 29er 😁
After reading articles/watching videos for weeks this is the first video that makes it really clear - not just the technical stuff about trail etc but how it actually affects your riding - and how it relates to stem length and bar width. Thnx guys!
Really good video and helpful conclusions. Appreciate your testing and input for us!
Best explanation on fork offset. I have the Blur also and have tried the different offsets but in 100mm Fox SC, at the time I wanted and incredibly fast handling bike. Fast forward 12 months and I have been getting stuck into Enduro and have just ordered a new Fox 34 in 44mm offset. It seems I don't like the twitchy bikes anymore.
A clear and concise explanation. Thanks!
Yay! I finally found the video I've been looking for. I just put the RS-1 with 51mm offset on my new Yeti SB100. I'm sure I got the right offset for my riding now.
Glad we could help out mate, and hope you enjoy that lovely new bike of yours!
[ST Wil]
nice work, mate. i have 2 bikes - the burly MegaTrail with a slackety-slack 64° hta, so running a Lyrik Ultimate with a crazy tight 37mm offset. it goes down hills like a champ! the other is a Spot Ryve 115, at 67.2° and running a fox 32 with 44mm offset. i find that on my Spot, a longer offset (51mm) is very twitchy on slow, tight corners. and less stable at high speeds. i then ran a 44mm offset, and the cornering at low speeds is more reliable. high speed control also improved. that being said, both bikes have the same anvl 32mm stem and 740mm wide bars. the odd thing, to me, is that subjectively the 51mm offset on the Ryve should help with slow speed cornering/climbing, but i dont see it. the high speed control on this bike is vastly improved, tho, as i have noticed. my overall claim is for me, 51mm offset on a steep HTA does not work well with a very short stem. YMMV
Interesting stuff. Well made video and very well presented.
Cheers Dave - glad you liked it, and really appreciate your feedback mate!
[ST Wil]
Good article.
Great informative video. But I wish this bike was ridden and tested as a dedicated xc bike which it is and not a 3/4 trail bike. Everybody talks about how it descends but I haven't seen a single video on how it climbs tight steep switchbacks or technical climbing features.
Hey Marek!
Thanks for watching and for your feedback - it's much appreciated!
As I mentioned in the full review, I actually tested the Blur as a full-blown XC bike last year;
singletrackworld.com/2018/03/first-ride-review-santa-cruz-blur-3-cc-xx1-reserve/
In answer to your comment, it does climb exceptionally well. It has a very stiff frame and the suspension is totally efficient even with the shock set wide open. The handling uphills is quite neutral and steady, and because the head tube is very short (90mm), it's possible to set it up with a very low bar height for maximum climbing power and efficiency.
Following that original test, I requested a frameset on its own from Santa Cruz, with the idea of building it up as a custom bike. I wanted to try it out with a 120mm travel fork and some burlier tyres, mostly to see just how far it could be pushed. Turned out to be a really fun bike too!
I'm actually turning it back into full-blown XC mode right now. Fox is sending me one of the new 32 Step-Cast forks with 100mm travel, and Hunt Bike Wheels has sent out some prototype XC racing wheels that I'll be able to talk about more soon. I've also just fitted a new longer/narrower cockpit setup, so it should end up being quite a sharper racer when those changes have been made.
Hope that info helps explain, but if you've got any specific questions for me about the Blur as an XC bike, by all means send them through mate!
[ST Wil]
Thank you for the explanation and taking stem length bar width into consideration! ^_^
I have an epic evo w a 42mm offset fork and a stumpjumper evo 29 with a 51mm offset and the stumpy steers better with a 63.5 HTA. I'll be swapping the epic to a 51 soon. It makes it handle like a bus in singletrack
Excellent information. So to clarify and check if you still feel the same a year later, you've no handling issues riding a evo 29 with 51mm offset, although a complete bike is spec'ed with a 44mm offset? Did you get a chance to ride the evo with 44mm offset? I'm trying to decided if I use a fork I already have (51mm offset) on a new evo 29 frame I purchased, or look for a 44/42mm offset fork. Thanks!
Sounds like it's comparable to caster for cars, thanks for this explanation!!
sick video sorted everything i'm pondering for my bike
Would love a direct comparison between the sb100 and the blur with 120mm SC fork.
I think the sb100 may be more your style.
Me too Daniel!
I've not ridden the SB100, but I'd love to check it out - looks like a cracking aggro XC bike!
[ST Wil]
Or try the Ibis ripley....
Jesper Lund , that Ripley looks really fun! I think the Ripley is more of a trail bike without any apologies about it. The Blur trail is a XC bike with a party attitude, right? I just bought a Blur trail because where I live I have a lot of smooth single track that I ride all the time and then occasionally I’ll go ride chunky stuff or desert riding is only a couple hours a way. Plus I do a couple xc races every summer.
@@coreymclernon How do you like your Blur Trail? How is it on longer rides with a lot of climbing both fire road and technical?
Excellent. Do the same for gravel bikes.
For an average rider, i'd say this offset thing 44 vs 51mm is pretty much bs. I personally went from a 51 to a 44 this season, no difference whatsoever. Why does everything have to be made so complicated? It just confuses people. Folks, don't think about this, just buy what is available atm of purchase if you are an average guy or gal just riding trails to stay in shape. More advanced riders can probably tell a difference no doubt.
I'm trying to work this offset out as my mate has fox 38s the grip 2 type I just got the fit4 38s on my new bike came with them but his has a sticker saying 27.5/29in below the wiper on the right fork mine don't and I'm running 27.5s his offset is ment to be 44 to 51 mine is 37 to 44 both being 44mm would I be able to run a 29 on the front or not they look no different side by side so he's coming over tomorrow gonna test this out! I mean my 27.5 look huge I don't see how the 29s would benefit me I'd never get on the bike! Just you seem to have more experience here it seems can you shed some light on this for me please?
@@Emtbtoday I wouldn't worry about the offset, especially if you're a pretty average rider. Your friends fork is a 29in fork, but you can put 27.5's on it if you want to. Yours is probably a 27.5 fork but go ahead and try his bigger wheel on it, you'll see instantly if it's a 27.5 fork.
Really interesting, thank you!
My pleasure Michele - glad you found it as interesting as I did!
[ST Wil]
Amazing video. Seems like the offset is not that important for amateurs, specially if you consider that the 51mm suspension sometimes is U$300 cheaper than the 44mm.
Great video, thanks for taking the time to really analyze how the changes to offset actually effected your ride out on the trail.
Question: What I have yet to figure out is...slacker head angles were/are used to make bikes better at descending, so why did companies not just continue to make bikes slacker and not mess with offset? Or conversely, if offset has the same effect as slacking the head angle, why did the bike companies spend the last 5+ years remaking their bikes to make their frames slacker, when simply changing to a reduced offset fork would have the same effect? What am I missing? Do offset changes not have the same "effect" as head angle changes? Can I pickup a used frame with an "out-of-date" head angle of 69 degrees and slap a reduced offset fork on there to get the same ride characteristics of newer models?
Although trail is the most important part of steering geometry there are other factors that affect how the bike feels. Wheel flop is one, and touring bikes often achieve the desired trail with slightly steeper head angles and shorter offsets to reduce flop a bit because you may be using front panniers. On a mountain bike I think a slack head may also be desirable because of the angle at which you're hitting rocks and things with the front wheel. So it might be better to go even slacker and add offset... Not sure at what point excessive wheel flop becomes a problem. The other reason you need to go slacker than before is longer fork travel. An HT that's 65deg with a 140mm fork at 25% compression will be about 71 deg at full compression.
Besides what Ben C mentions, a slacker head angle increases the front centre, while a shorter offset reduces front-centre length (both increasing trail). Slacker indeed means a more beneficial angle for the fork to absorb impacts and less over the bars risk, a shorter offset might keep more weight on the front compared to a bike with the same trail with a slacker head angle.
Would be interesting to see the difference with different stems and frame sizes.
So you could have the same seating position with different frame size and different stem lenght.
I mean a small frame, 50mm stem and huge offset. Compare to medium frame, 30mm stem and short offset.
Great video! Very well explained.
very well explained! 👍👍👍
Check out Part One of our detailed article about fork offset right here: singletrackworld.com/2019/04/what-is-fork-offset-and-why-does-it-matter/
Really good stuff Wil!
Excellent info,
Thanks
Great video, thanks a lot! I see lot of useful content at your channel, subscribed 👌
thank you!
great explanations, thank you
Does offset change how the bike handle steep sections? The difference between the two options with Rockshox is almost 10mm, you say that it shorter offset makes it more stable at speed but having the front wheel 10mm further out in front of you and also increasing the wheel base by 10mm not do anything for stability?
great explanation. Thanks.
Nice information. Currently I have an Specialized Fuse Comp with a 120mm fork 51offset. I’m planning upgrading the fork to a 130mm or 140mm. Would be wise to reduce the offset to 44 or 42?
Glad you found it useful Roig!
That's an interesting question you have on your Specialized Fuse hardtail.
Firstly, do you know if the frame warranty will be voided if you put on a longer fork?
Generally most frames will have a limit as to how long of a fork you can put on there, so you'll want to check that out first before assuming you can go much longer on travel.
If you do end up going to a 130/140mm travel fork, remember that you'll be slackening out the head angle, as well as slackening the seat tube angle and lifting the BB height. So bear in mind the affect that will have on your riding position.
Assuming you stick with a 51mm offset, that slacker head angle will still increase the trail figure. This will steady the steering behaviour a little bit. However, going to a 42/44mm offset will take that stability even further.
A couple of questions to ask yourself;
- What stem length are you using at the moment? And if you went to a reduced offset fork, could you comfortably go a bit shorter on the stem length? Or is the cockpit already a bit cramped?
- How twitchy is the handling at the moment? Do you want to slow down the steering and improve straight-line tracking on the descents?
The cockpit question is an important one, because bar width and stem length play an important role in determining how much leverage you have over the front wheel. In my experience, a reduced offset fork plays best with wide bars and a short stem. But if your frame is already a bit short on the top tube, going to a wider bar/shorter stem may not be ideal.
Hope that helps mate!
[ST Wil]
Singletrack Magazine Thanks a lot. The stock stem was 50mm I change to a 45mm. And the stock bar was 750mm, currently have a 760mm. The Fuse BB height is very low with the stock tires 3.0 Now I have 2.8 rear and 3.0 front. If I change the fork I will go 2.8 front and rear to compensate. Thanks for you time.
Not Fork Offset related but,
I'm Loving the trails you have there.
And I Think a Tracey Hannah meet should be organised it would be epic..
And to read all about the results of the fork offset test, check it out here: singletrackworld.com/2019/05/short-vs-long-fork-offset-testing-on-the-santa-cruz-blur/
Excellent video my friend. I never heard of Castor effect before but it's nice to have a name for something I experience every ride.
I eagerly await PVD's take on this. Don't understand any of it, but I know he'll have something to say.
excellent information will you need to change spacers on brake caliper.
Great video!!
Thanks Chad!
[ST Wil]
Great video! 👍
Cheers mate!
[ST Wil]
Good video mate
Can anyone help me, I have a new specialized chisel and can upgrade the fork to a fox rhythm float 32 100m with a 51 offset! Will the be a plus or a negative as an upgrade
Very helpful video thank you
Glad it was helpful!
Very good video! Is there any way to find out in an easy way what rake or offset has your FOX Fork?
What length stem and bars are being used in this test?
I agree totally 👍👍👍
I have a 66° headtube angle on my fuse, does anyone know how a 37mm offset fork affect it?
So on a Santa 2021 Cruz Tallboy 4 a 51mm offset fork would make the bike go around corner’s easier because of the slack 65.6 head angle?!
Please try 68.5 head angle/51 mm rake (very nervous at slow speed and steep curvy hills) and 69.5 angle/xx rake meaning the same trail (100 mm travel both), thank you!
I am suprised that Santa Cruz doesn't offer a 120mm for in their Blur build kits. Have you heard if this is possible in the future? I am eyeing a new Blur Tr in the next few years, but would rather have the 120mm fork and not the 110mm I believe?? Thanks
Any plans to test angled headsets on this bike? With 120 mm forks looking at 66 degrees? Would be interesting ro know how capable you could make it. Would also be good to test efficiency loss on climbs.
As far as I know, at santa cruz frames the headsets are usually integrated, which makes it very hard to make any angled headsets.
Hi, I have a SC Highball with 100mm 32 Stepcast fork, looking to upgrade it to a 120mm 34 Stepcast , what offset do you recommend and do you know how much this would shorten the reach by and how slack the head tube angle would be ? Thanks btw great video
So increasing the offset will make the bike slacker and wheel base longer right?
I hv a 27.5 160mm fork with a 42mm offset with a 66 deg head angle on a 150 travel bike. I still crash alot. But it does feel more stable going fast thn going slow. Maybe thts y i crash alot (besides crappy skills). Bike makes u want to go faster all the time.
This video is for 29 inch wheels. Your 27.5 fork has the longer offered offset with the 42mm.
@@justinwbohner really? What is the shorter offset offered by rockshox or fox for a 27.5 one can buy after market?
@@stevent1565 Because of geometry. The 29er wheel axle to ground is taller than the 27.5.
what if I'm looking to downsize the fork in general? I have looked at the geo the bike stock comes with a 44mm offset. The ht angle will be changing by +1 deg . so for this example would you stay with the spec'd 44mm offset or get a 51mm?
What about the specialized tires?? Which section did you tested? I'm looking for something grippy whith low rolling for my tallboy.......i know i'm out of topic, but, if you can tell me something.....
If I'm going from a 51mm to a 44, will I need a new headset or any other hardware? Thanks in advance! Cheers!
Quality content! 🤘👍
I ve a really weird experience. I ve two nomads. One in small, the other medium size.
The 46mm offset doesn t feel good with the small frame. The bike is far too agressive in the turns. The medium is much more calm with the 46mm offset and still alive.
Now i m very confused. I m thinking to buy a shorter offset for the small frame, to bring back some stability. But the wheelbase is shortening then, too. I don t know what effect this is going to have?
On 29" forks the difference is 5mm and not a huge difference. On 27.5" it is 9mm difference which is plenty.
Thank you! I learned something new. :-)
negtive degree stem will make the thing worse for 51 offset right? i guess i will change to positive degree
I'm currently using a 35mm stem with a 42mm offset fork and the handling seems a little bit twitchy. would matching the stem length to the offset help with this? say 40-45mm?
What is the trail measurement for a standard Blur and a Blur TR? (Not the modified version you have)
Which offset is better for corner grip on loose gravel?
TL;DR there's not much difference, it's for fine tuning a ride, and there are inexplicable tire changes when swapping forks.
Great job. How do you predict size of bike comes into play? If I've got a XL bike with a big wheelbase...and the chainstay length is the same for all sizes...meaning that the front and center is growing disproportionately as you go up in size ....wouldn't i benefit from a 44mm offset and a 32mm i9 stem? 😊😷
Hi guys, question fo you guys, I'm thinking about getting a custom build on the " Yeti SB 130 turq frame & it's a particular question on the fork offset as you know Fox 36 fit 4 has 44 fork offset, but I would like to put a Rockshox Lyric but this has a 42 will this make the steering more stable on the downs ? But going up how will it affect the climbing ?
Kind regards Drew
2:55 nope,the one that tends to keep your front wheel straight when riding without hands is the conservation of angular momentum.
The caster effect stops the handlebars and front wheel twisting. Angular momentum stops to bike from tipping over
I have a intense carbine 2018 29er.. its it ok to use 44mm offset? Thanks
is the offset in the CSU or in the lowers?
2:03 You did not mention the offset at the crown.
Yo Johannes!
Apologies if there was any confusion there for ya - the offset is the measurement of how far forward the hub axle sits in front of the steering axis. This offset can be found in both the crown and the dropouts, though the most important aspect is the total amount of offset.
Hope that helps explain, but if you've got any more questions, just shoot them through mate!
[ST Wil]
@@singletrack I already knew this, I just thought you should have mentioned this. Now you have, well put. Thx.
Will gives a detailed explanation of both types of offset (crown and dropout) in Part one of this feature here :-) singletrackworld.com/2019/04/what-is-fork-offset-and-why-does-it-matter/
[ST Mark]
what is the HTA on the Blur?
your bar is 780mm 20 sweep?
Hay there 👍what happens if I increase my fork length 170mm too 200mm is that too much . Is there a maximum set by manufacturers? thanks
The difference in axle to crown measurement between a 170mm single crown fork and a 200mm dual crown fork is about 15mm so the difference isn't that major. There will be less than a 1° change in head angle/ seat angle. You'll lift the bottom bracket by roughly 6mm and lose 8mm roughly of reach. If that along with more stiffness and travel up front is what you want then go for it. It will probably void the frame warrantee if you have one because the dual crown will put more stress on the head tube due to more stiffness and longer axle to crown
Harder to ride no hands with my offset fork. That's my only con. Other than that reduced offset feels great for me.
this trend just goes back and forth
Do you have to change brake mounts when swapping 44 and 51 offset?
No
I have a bit of trouble manualling off drops on steep terrain at slower speeds. would one or the other offset help with this?
No, you just need to learn how to manual
What part actually is different, the steerer tube or the lowers?
Yo Eskohl!
In most forks, the total amount of offset is made up of both the lowers and the crown. However, if you buy a 44mm or a 51mm offset fork, both with have identical lowers - the difference between the two is entirely in the crown.
[ST Wil]
I think u have it wrong . Longer offset means greater caster means more nimble and lighter with the steering. 44 should give u less caster if anything but then I doubt we could feel 5 mm difference in offset.
Shorter offset moves the wheel backwards and therefore trails further behind the steering axis. This leads to more stability. Think of it like caster wheels on a shopping trolley, the further back they would sit, the more stable they will be
Great reviews, thanks Wil! After testing the blur with 100/120mm travel, how do you find it compared to a bike with travel in the range 140-150mm?
Which offset ist series at Santa Cruz Tallboy 2019??
Tallboy 4 comes stock with the shorter offset forks
Ive got 46 offset.. Im sitting between the best of both worlds
Actually, you are wrong in one thing. More trail = better stability AT HIGH SPEEDS, less stability AT LOW SPEEDS. Bike becomes unstable, harder to ride without hands with less offset=more trail.