So I’m currently running a 100mm Lefty, on a trail SL bike. I’m looking at making it rigid by replacing the fork. I’ve a set of reducing headset bearings, so the 1.5 isn’t an issue.

What I don’t understand is a) how long the replacement fork needs to be, b) does it have to be a straight fork, and c) aside from a new wheel and stem is there anything else I should be aware of?

26 or 29 inch wheels?

You can find various lengths of rigid fork, they are sized to represent a sagged suspension fork. If you want to preserve the geometry as it is now, buy one that measures close to the axle-crown measurent of your lefty and subtract sag (or measure with fork sagged).

Or you can get one slightly shorter for quicker, twitcher handling. IIRC 10mm shorter will increase head angle by roughly 1 degree (someone correct me if that is inaccurate).

Sorry, its a 26er.

So, just measuring the uncompressed setup axle-crown is 475mm and I think the sag is roughly 20mm/25mm. So I should be looking at a fork of 450/455mm.

Out of interest, why do you mention getting a shorter one? Is that just a general trend? Would getting a slightly longer one be equally valid, and have the reverse effect?

So, after having a look at some forks lengths, lots of the 29er ones seem to be only 10mm longer than my 455mm target. So would it be acceptable to put a 29er fork + a 29er wheel on the front?

You’ve forgotten that after adding the 29’er fork’s 10mm, the bigger wheel wll add another 38mm or so. Will end up very slack

You can put a 26″ wheel in the 29er fork, but it’ll look strange and the longer fork will slacken out your handling.

Go for a 445/450mm fork, steel or carbon. You might find a cheap steel fork rather dead feeling though. Also should add that most rigid forks are straight-legged now.

What length steerer do you need? I have a Ritchey Pro carbon MTB disc fork 450mm a/c I had on my Cotic Soul commuter somewhere around the house – pm me if interested.

Or you could put a rigid lefty fork on and keep your wheel and stem. Blackcatbone do one.

http://www.blackcatbonebikes.com/

It’s called Lucy

sexy Mo fo!

my word that is nice!

Easy to make too.

back to the OP – you will want a ‘normal’ 100mm suspension corrected fork so one with about 440-450mm a-c. Lots around in carbon or steel.

You can easily fit a 29er wheel and tyre in a 26″ rigid fork as there is plenty of clearance but it will slacked the bike a bit (like fitting a fork that is too long). It is normally about 1″ extra gives 1 degree more slackness I believe.

29er rigid forks are about 465-470mm a-c. They can of course be used with a 26″ wheel where the bike was designed to use a 120-130mm travel fork.

Why do you want a rigid fork,ive always lusted after a lefty? are they no good or is it a lock out issue (i thought they had lockout ?)just curious thats all .

Chainline, those Blackcatbone forks are lush. First time I’ve seen them, and they have gone on my long term / lottery win wish list. I see they have no prices, so am guessing even more expensive than cannondale ones!

Trevron73, the reason I’m after a normal rigid fork over the lefty is that I’m trying to convert the bike to a workhorse delivery bike, and so want to fit full length mudguards. Not to mention that it will look less desirable to thieves, lower running costs etc. For the record, I’ve never ridden a nicer fork than the lefty for off road mtbing, they are amazing.

suffolk, cheers for the offer, think its a little ott for what I’m after.

Cheers everyone, think I’m getting the picture now. Probably aiming for a cheap 26 fork, may toy with the idea of a 29 wheel at a later date 🙂

Pipedream do their 450mm steel fork for £50 IIRC, or Salsa do a variety some with mounts for a bit more, think they are 445mm