Fork fitting fun

[mxg01]

I'd like a rigid fork on my mountain bike that can take a rack. I'll stick with the existing 27.5" wheels. To use these and not reduce the front height I think I need a 29" fork. I don't want to miss anything so I need a bit of help. The basic question is -

Will this:

https://www.bike-components.de/en/Surly ... rk-p38148/

Fit this:

https://www.halfords.ie/cycling/bikes/m ... -22-frames

Currently the bike has a Rockshox Recon fork with these specs:

Wheel size: 27.5"
Steerer: 1 1/8"
Steerer length: 265mm
Disc brake mount: Post Mount (PM6 - Direct Mount 160mm)
Maximum Rotor Size: 203mm
Drop out: 9x100mm quick release
Max Tire Diameter: 710mm
Max Tire Width: 62mm
Axle to Crown: 486mm
Offset: 42mm

As far as I can tell, it will fit. The Axle to Crown on the Recon is 486mm and on the Surly fork 468 mm. About 20mm sag on the Recon. Offset is similar enough, 42mm on the Recon and 47mm on the Surly. The axle on both is 9x100ml QR so that's ok. The brake mounts are different, the Recon has Post Mount and the Surly has IS mounts. I can buy an adapter to cope with this. Front brake is Shimano M395 and the wheel has a 180mm rotor.

I doubt I'll swap forks very often. Am I missing anything?

[NetworkMan]

If I were you I'd want to calculate the trail for each fork and make sure it was similar. Let's see if someone who understands suspension forks chips in ...

[alexnharvey]

I think if the offset and fork length are very similar then trail will be also, as offset increases trail decreases.

[531colin]

Here https://www.voodoocycles.com/hoodoo the head angle is given as 67.5 degrees. That is way outside my experience.
Combined with a short fork offset that gives a long trail; I think you will find that adding a front load to a long trail bike has more effect on steering feel than adding a front load to a bike with average or short trail.
I think in the end you will have to try it and see if you find the steering feel acceptable.
The rigid fork is 5mm longer offset than the suspension fork, this is a very small step in the direction of shorter trail.
Fitting a shorter fork than the suspension fork will drop the front of the bike, in round terms a 20mm shorter fork will steepen the head angle by one degree. Touring bikes (designed to be ridden either with or without a front load) commonly have 72 degree head angle combined with 45mm offset, but its impractical to drop the front of the bike the required 80mm or so.
Just for my own curiosity, how does the bike steer no hands? I imagine it would take exaggerated angles of lean to make the bike go anywhere other than "straight ahead". By comparison, on a short trail bike its easy to slalom the cats' eyes no hands.

[SimonCelsa]

I did a similar thing a few years ago. Swapped some cheap suspension forks with some Surly Ogre ones. Not all the scantlings were 100% correct but it works OK. I have to say the old suspension forks were quite a bit more comfortable, and, although the Surly ones are lighter I don't seem to go much faster.

The saving grace is that I purchased mine at £79, not the £150 they are asking now!!

Was it worth it?? Still not sure about that one. I was doing some long mileage days and thought the saving in weight would make a noticeable difference. Which it didn't really.

Good luck anyway

[mxg01]

Thanks for the replies.
No handed the bike just goes straight on. I'm not brave enough to lean very far anyway. It's great on single track in terms of steering and you can really whip it around corners.
I'd thought about weight, there should be a reduction of about a kilo in fork weight.
I'll maybe give it a go. I could leave the steerer uncut so if it's a disaster I can sell the fork.
Thanks again.