You don't need to be an 'investor' to invest in Singletrack: 6 days left: 95% of target - Find out more
It's maintenance time and the fork on my daughter's 15.5 Trek Skye has died so I'm going to replace it rather than repair as it was never great in the first place and she rides the bike way more than i expected which I'm loving. The original fork was a 75mm travel Suntour spring thing but I'd like to replace it with a Rockshox air for as I've got the bits and am used to servicing them. They start at 100mm and I would doubt there is any problem going from a 75mm to a 100mm fork but how far do you think I could go before it will make the bike just funny to handle? I'm not looking to get huge travel and 100 would be fine but I also like to keep my eye open for special offers so it is useful to have an idea of what the limits are
I fitted some Fox Float 80mm to my lads Carrera Blast, the axle to crown wasn't much different to the ones I took off.
I would have thought that you'd be ok with 100mm, just use more sag.
I went from 80mm cheap coil fork that had seized up to a 120mm air fork on a carrera frame.
The forks were suntour XCM coil, to suntour epixon air.
The difference was very significant. In a good way.
@mattyfez - did the handling feel like it had gone weird at all?
My updating projects of old XC hardtails...:
30 mm or 40 mm more travel will be fine and the bike will be much, much more fun.
I use old XC frames which - were sold with 100 mm forks - with 130 mm. I still use the bike for XC and not for jumping or similar. Guess the frame would fail.
So - keeping the frame snapping issue in mind - more travel is more fun!
30 mm or 40 mm more travel will be fine and the bike will be much, much more fun.
Cool thanks. That means I could probably also get away with 110 which widens my options a bit. Fun is good. I can't see the frame snapping as my daughter is quite small and to the best of my knowledge doesn't go hucking off any big drops here 🙂
Im the olden days they used to say 20mm (which is generally the next niche up), but only as you say a rule of thumb because often the same frames were sold with different travel forks - so the entry level HT might have 80mm RSTs and the top of the range 100 or even 120mm Fox, so in theory you could leap from 80mm to 140mm and still be within the rule.
Its the Axle to Crown that matters though and short travel forks aren’t always ‘short’.
Its the Axle to Crown that matters though and short travel forks aren’t always ‘short’.
Good point actually. I seem to remember that there is actually quite a lot of space in the current forks. Will go measure
I’m running 130mm forks on a 100mm bike. Hasn’t upset the handling as far as I’m concerned - just raises the front up a bit to where I actually like it. If I run it at 100 (it’s a u-turn fork) it feels twitchier - although it does climb better in 100mm as the front wheel stays down better.
I think I'm tempted to go from 75 up to 110 as that doesn't seem to big a jump compared to what folks here are doing and seems to work and it widens my options as to what I can buy
thanks all
I run U-Turn Revelations (100-130 mm) on an old 80 mm Anthem frame. Those replaced U-Turn Rebas (85-115 mm). The Revs are an improvement except for very steep climbs. Set on 100 mm, it's an excellent XC trail bike. On 130 mm, it's more stable on descents but a bit slower steering on tight XC stuff. Adjusting stem length and bar height can make a big difference. If it were me, I'd probably look for 110 to 120 mm forks.
People say A2C is the deciding factor. However I think there is perhaps more to it. Perhaps stresses when using longer travel. For example this is on Cotics warranty page
Note: Fork compatibility is defined by travel not length. We understand that some manufacturers forks are shorter in height than others, but this is irrelevant. If you run forks with longer travel than we have stated for a given frame, warranty is void and likelihood of damage or failure of the frame is high.
I know that may just be there opinion. But it must come from something
I know that may just be there opinion. But it must come from something
Longer travel forks generally mean more aggressive riding and bigger crashes. That will cause more stress on the frame. The AC length itself won't make a huge difference if you're just riding gentle XC trails. Even repainting a frame will void the warranty, they are written by lawyers whose job is to avoid paying out whenever possible.