converting SUspension fork to rigid fork - details?

[d_douglas]

Hi all,

I am in process of ridding my son of the worn old suspension fork on his commuter bike to make it more commuter friendly and I need some help.

It is a 10+ yr old RockShox Reba or Judy that has leaks and work stanchions. I think the travel is either 80-100mm. I have locked it out so at least it isnt bouncing.

The frame is a 16" Norco hardtail (name escapes me, but its a decent alloy one about 10yrs old).

If I replace the fork with a rigid equivalent, how long should the A-C be? It is for conmmuting so I dont want it to be a sled. The frame takes a straight steerer and uses disc brakes only.

Am I looking at a 425-440mm rigid fork? One shop I called suggested a 460mm, but that sounds too tall for this purpose.

I guess secondly, does anyone have one for sale that is affordable?

[AngryScientist]

What does the current fork's AC measure in it's current locked out state?

[p nut]

Assuming this is a 26” mountain bike w v-brakes? And 1 1/8” HT?

I’d stick to ~420mm.

Surly Troll fork is currently available. May be able to find one used here or eBay.

[nmrt]

I think for suspension forks, the a-c to keep in mind would be the actual a-c minus 10-15% sag. This should be the a-c for the rigid fork.

[Ken Robb]

If I did a conversion like this I would probably choose a fork that would trade a bit of steering quickness for more stability for a commuter.

[Alistair]

What wheel size? 26, 650/27.5, or 29er?

What headtube? 1.125" or tapered?

QR or TA?

Assuming 26 wheels, straight head tube, and QR, you're best bet is finding a used Kona P2 from that era. Swap/replace crown race, install fork, and you're done.

[Veloo]

I'm going through this process for my 1997 Quadra 21R forks. I think the elastomers finally crapped out this year. I have been noticing slight discomfort in my commutes lately.

Rebuild kit would be about $70 USD but I was hoping to save some weight wih a rigid fork and not sure if the plastic parts of my fork would survive a disassembly/reassembly.

Urbane has this which is the right price but only 0.6 lbs lighter and the A-C is 395. Supposedly my A-C is 408.
https://www.ucycle.com/fork-26-threa...-w-bosses.html

Bit of a(nother) crazy thought entered my head: what if I just 3D print some rigid elastomers. Don't care about suspension since this MTB is a commuter now and the 3D parts so far seem to be fine in compression, just not so much in tension.

So some food for thought. If you want to try this crazy idea, I'd be happy to print some rigid elastomers for you.

So regret not getting that $100 carbon rigid 26 canti fork from Nashbar many years ago.

[Spoker]

I would go as low as you can go with your BB height . The steeper HA will be OK but having your feet close to the ground is safer and nicer.

[coffeecherrypie]

Originally Posted by Veloo

So regret not getting that $100 carbon rigid 26 canti fork from Nashbar many years ago.

I had that fork, pretty sure it was "carbon" in name only. Very heavy.

[Veloo]

Here's another option if you're up for it and can find polyurethane rod.

https://www.youtube.com/watch?v=LY2jA0sILms

[mstateglfr]

Look at Carver fork. They come in multiple A-C options and are simple but solid. One is in the 420mm range.

[litcrazy]

I imagine it’s quick release and if 10 years old is possibly 29er.
If 29er you’ll be happy with 468mm axle to crown. If 26” likely 440.

I love salsa quick release cro moto forks but they are getting harder to find. The soma range steel ones are supposed to be similarly more supple than surly forks. I have the soma/potts collaboration is 420 and it’s wonderful. A nice steel fork should feel a lot better than the old shock and is less worry when locking a commute than carbon in my mind. Carbon is more vulnerable to the person next to you whacking it by accident as they lock up.

Soma has been having lots of 15-30% off sales. If you can’t find the right length in a salsa form, I’d sign up for the soma email list and get a tange form at the next sale. The should have the right length. I think they do 425, 445, 468, 480 still.

[PacNW2Ford]

My build sheet for a 2007 IF Steel Deluxe built for a 80mm travel suspension corrected rigid fork shows a 430mm A-C dimension.

[PacNW2Ford]

^ for 26” wheel.

[KonaSS]

It is entirely possible to overthink this. I would take the axle to crown measurement of the current fork and subtract ~20mm for sag, and then look for something close-ish to that. 15-20mm either way isn't going to matter.

Put another way, in the last 10 years I have ridden XC mtbs with head angles that range from 72-66 and all of them would have worked just fine as a commuter.