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Fork offset

StiHacka

Compensating for something
Jan 4, 2013
21,560
12,505
In hell. Welcome!
I feel that flat pedals just don't give enough safety and the risk of slipping one's foot or lose contact mid-air is very dangerous. Perhaps if someone invented some device that would wrap around the foot and that would secure it safely in place might work? :think:
 

Happymtb.fr

Turbo Monkey
Feb 9, 2016
1,913
1,268
SWE
There has been quite a few short travel xc/trail bikes lately with short offset forks, with not specially long reach and without extremely slack HA. For example Specialized Epic, Yeti SB100, Giant Trance 29 and maybe more... this trend does apparently not follow what Transition said (longer reach, slacker HA, short stem and short offset)
It might be another way for the lizards to constantly renew the market but I hope that there is more to it since I'm waiting for a 42mm offset fork for my trail bike! :D

On another topic, this got me thinking :
People really need to stop confusing "steering" response/stability/agility with "leaning" response/stability/agility while discussing offset. They are two very different things.
I have two bikes and one is harder to lean and doesn't turn as well as the other. What can I do to improve its ability to lean and turn?
 

Rhubarb

Monkey
Jan 11, 2009
463
238
I have two bikes and one is harder to lean and doesn't turn as well as the other. What can I do to improve its ability to lean and turn?
I am finding the same is true for both of my current bikes. One being a 160mm (F) x 140mm (R) Trail bike, and the other 170mm(F) x 160mm(R) AM bike. The issue only became apparent when I moved to my current location and started riding the local trails. There are a lot of tight corners (not switchback), flat turns or with small to mid support, corners that hug the trees (not much shoulder room), and corner to corner sections.

I find that my trail bike is quick as lightning, turns on a dime and is effortless. I can pick the front wheel up to set myself up between corners, jump out of turns, and I can lay this bike flat.

On my mid travel bike everything is much harder unless the trail opens up. Since I am doing a lot more trail riding and I expect this to continue, I have been trying to pin down the differences and see what I can do to make the bike more agile and quicker in the woods. Changing the stem from 40mm to 50mm made a huge difference and really caught me by surprise. This is one of the most notable changes I have made, in that I instantly felt the difference in handling. This was mentioned in one of the RM threads, so happy it was posted.

I have looked at all of the numbers for these 2 bikes, and the main differences are:
Rear travel - 140mm vs. 160mm
Wheelbase - 1135mm vs. 1195mm
Head Angle - 66.5* vs. 65.5* (more or less)
BB height - I haven’t spent much time looking into the actual numbers. I have longer travel forks and running various tire volumes, so the chart numbers will not be accurate.

At this point I feel the main differences are Head Angle and Wheelbase. Head Angle for steering and Wheelbase for leaning. My plan is to change the 170mm Lyrik for the 160mm Pike that is on the Trail bike. This will lighten the front end a little, drop the Head Angle, lower the BB slightly. I compressed the Lyrik but 10mm and measured the Wheelbase and the is only a difference of around 3mm.

If the Pike improves the feel of the bike then I will reduce the Lyrik to 160mm. My goal is to make the mid-travel bike more agile, but have the extra travel and suppleness for bigger mountain days.
 

FlipSide

Turbo Monkey
Sep 24, 2001
1,385
818
Since starting the thread, I have upgraded my bike to an Enduro monster: Devinci Spartan LTD, with a 180mm Lyrik RC2 having a short offset.

The bike rips for pretty much everything. I have not tried a long offset version of the fork for comparison, but I can certify the short offset fork does not make the handling sluggish or anything. I am actually surprised how nice the bike rides even for mellower trails. I was expecting to be overbiked very often, but that doesn't really happen. It turns out I was previously underbiked. I had to adapt a little bit for the tight corners at first, but I believe the long wheelbase and slack HA are more significant contributors than the short offset.

Comparison Old bike (Pivot Mach5.7c, Small) ==> New bike (Devinci Spartan, Medium)
Reach: 389mm ==> 445mm
HA: 67 ==> 65
WB: 1102mm ==> 1200mm

I'd suggest to anybody debating between a short and long offset to go for the short. My initial concern (putting a long offset fork on an Enduro bike to liven it up) was a total non-issue.
 

Happymtb.fr

Turbo Monkey
Feb 9, 2016
1,913
1,268
SWE
Thanks for your comments @Rhubarb and @FlipSide !

The longer stem is something I tried too. I went from 35mm to 50mm and the steering became more quiet when riding rough section. I have done this on 2 bikes and the 50mm stem was better in both cases. I don't get the hype for super short stem... maybe they're a solution when you go super slack with really short offset?

I did some tinkering yesterday and did 2 changes on the worst bike: I lower the stem and went for firmer shims on both compression and rebound in the fork. After a first ride it seems to work: I have less pogo stick behaviour from the fork and it seems to be easier to lean the bike. I definitely need more riding time on this since I just went for a short ride and had obviously great expectations from my mods... :D
 

William42

fork ways
Jul 31, 2007
3,916
651
Since starting the thread, I have upgraded my bike to an Enduro monster: Devinci Spartan LTD, with a 180mm Lyrik RC2 having a short offset.

The bike rips for pretty much everything. I have not tried a long offset version of the fork for comparison, but I can certify the short offset fork does not make the handling sluggish or anything. I am actually surprised how nice the bike rides even for mellower trails. I was expecting to be overbiked very often, but that doesn't really happen. It turns out I was previously underbiked. I had to adapt a little bit for the tight corners at first, but I believe the long wheelbase and slack HA are more significant contributors than the short offset.

Comparison Old bike (Pivot Mach5.7c, Small) ==> New bike (Devinci Spartan, Medium)
Reach: 389mm ==> 445mm
HA: 67 ==> 65
WB: 1102mm ==> 1200mm

I'd suggest to anybody debating between a short and long offset to go for the short. My initial concern (putting a long offset fork on an Enduro bike to liven it up) was a total non-issue.
You live up in whistler right? I'd imagine most of your trails involve some pretty punchy and steep descents that would be a straight up blast on a downhill bike, as well as some longer climbing sections? For people living in flatter areas where the descents are less gnar, would you still lean that direction?
 

HAB

Chelsea from Seattle
Apr 28, 2007
11,580
2,006
Seattle
You live up in whistler right? I'd imagine most of your trails involve some pretty punchy and steep descents that would be a straight up blast on a downhill bike, as well as some longer climbing sections? For people living in flatter areas where the descents are less gnar, would you still lean that direction?
I've experimented with shorter offset forks too, and I actually notice a bigger difference (for the better) at tighter, medium speed stuff with higher degrees of steering input than I do going fully rowdy. There are few significant downsides as far as I'm concerned.
 

FlipSide

Turbo Monkey
Sep 24, 2001
1,385
818
You live up in whistler right? I'd imagine most of your trails involve some pretty punchy and steep descents that would be a straight up blast on a downhill bike, as well as some longer climbing sections? For people living in flatter areas where the descents are less gnar, would you still lean that direction?
I wish I lived in Whistler! :brows:

I live on the East Coast (Québec) and I ride mainly at MSA. There is no shortqage of gnar over here, but I don't ride the super gnarly steep and rough pure DH stuff with that bike. My typical day has a bit of everything: 4-5 gondola runs, 50km total, with 800-1000m of climbing. Out of that 50km, one run will typically be very XC (like 25km) with a lot of punchy climbs and the rest will be 5-10km loops with a bit of everything, from groomed singletrack to DH stuff.
 

Happymtb.fr

Turbo Monkey
Feb 9, 2016
1,913
1,268
SWE
I have been on a short offset fork for nearly three weeks now and I don't notice that much difference... the only thing I find is that it feels like there is more weight on the front wheel. It could also be explained by the shorter front centre...

I just changed the offset, the rest is the same: same bike, same fork (except offset obviously), same everything else.

Maybe I am dead inside?