Bit of a random one this potentially.
As part of my 'faster mtb' for Gent Wevelgem i ended up buying some new forks for the Parkwood. These are 450gr instead of 2.3kg. Carbon, rigids.
Anyway, i was doing some measuring today after looking at this pic from the new forks.
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These are showing a axle/race of 480mm. Just measured up the Parkwood and that is at 530mm for the same measurement.
So apart from the obvious part of lowering the front end, how much of an effect are we looking at ? Quite significant i'd assume ?
Now lets assume i use a bit of steerer length and just stick the stem 30-50mm up with steerer spacers, will it then negate the effects of the lowering etc ?
I don't mind a little bit lower, as i'm assuming that this will help with body position for the road stuff, the bike won't be used off-road at all, so don't worry too much about trail handling. But i'd have thought dropping it by 50mm is likely to give adverse effects even on the road ?
Your head angle will be 2.5 deg steeper. Which may or may not be an issue on the road but the steering will be quite quick.
Your head angle will be 2.5 deg steeper. Which may or may not be an issue on the road but the steering will be quite quick
Not really.
Parkwood forks probably compress 30mm when you get on, so actually only a degree steeper in practice.
What he said. Someone once told me that an inch in fork lenth equates to roughly 1 deg head angle so nickfrogs 2.5 is probably more accurate.
Hmmm excellent point Brant....something i never considered actually.
I'm guessing then 1 deg isn't going to be night and day.
I'll give them a whirl then once they make the slow boat over from China 🙂
nickfrogs 2.5 is probably more accurate.
No it's not, suspension forks sag, rigid forks do not.
I’m guessing then 1 deg isn’t going to be night and day.
It'll be fine. Remember when setting frame geometry for use with sus forks designers are looking for a compromise between too slack when unweighted and too steep when deep in the travel. The sweet spot will be around about but probably shorter than just the sagged setting.
Was gonna mention sag of suss forks. Plus the further compression as you go over stuff.
None of that with rigids.
I've been looking at putting rigids on a Orange Clockwork 100 frame that I have lying around to make a big tyre clearance gravel bike for the local forestry tracks, and this has been my thinking.
At the cost of aero, you could always run a wider tyre up front to slacken the fork angle a bit.
I swapped out the 26x4" JJ rear this morning for 700x31, keeping the 29x2.35" up front. Surprisingly enough, the Wazoo felt rather more spritely on the commutes today, especially up the inclines on the way home!
It used to be thunk that a 420mm fork corrected for 80mm sus forks, 440mm for 100mm. So you could extrapulate from there bearing mind that longer folks sag by more percent and the designer's inside leg measurement.
It used to be thunk that a 420mm fork corrected for 80mm sus forks, 440mm for 100mm. So you could extrapulate from there bearing mind that longer folks sag by more percent and the designer’s inside leg measurement.
Those dims with 26in wheels.
29in 80mm fork = 470mm rigid.
29in 100mm fork = 490mm rigid.