Svet

Hi there! I know the answer to this is likely to be "it depends", but I'll give it a shot anyway.

I have a Giant Central Park hybrid from 2003 that I use for commuting and touring - it serves me well. However it came with a pretty low-end SR Suntour fork (something like https://www.allterraincycles.co.uk/product/116991.html) that was never really much use and is now beginning to really show its age. I'm pretty keen to swap it for a rigid fork, and I really like the idea of the Surly Cross Check (https://surlybikes.com/parts/cross-check_fork/).

However...the current crown-to-axle length seems to be about 470mm, or ~450mm compressed. The Cross Check is documented as 400mm.

I do like the idea of bringing my front down somewhat, and I know it's a matter of personal preference, but would this be a totally ridiculous swap? Reading over other threads I see people "um"-ing and "ah"-ing over differences of 10mm, so would a difference of 50mm just completely mess things up? I'd love to hear from anyone who might've made a similar change!

Many thanks for your help.

FastJake

I've gone the other way before, putting a suspension fork on a MTB that was originally rigid. It definitely jacked up the front end, but I never measured to see how much. Despite lots of people saying that it screws up the geometry, I never had any issues. The way I see it you have two concerns:

- Your bottom bracket will be lower, which may cause pedal strike if it's already low (unlikely.)
- Someone may correct me on this, but I believe the lower front end will theoretically make the bike's handling faster and twitchier.

Whether these differences are a problem I'm not sure. You're looking at about 2-2.5 inches of drop on the front end, which sounds like a lot to me. Maybe hunt for a suspension corrected fork if you can?

*Edit: good call Burton. Check out this fork: https://surlybikes.com/parts/karate_monkey_fork/

Burton

Surly also makes forks that are specifically corrected to replace suspension forks. Whats the attraction with this particular fork which is designed ONLY for a rigid frame?

Svet

Hi guys, thanks for the advice! As you can see I'm kind of new here and it's great to see people so forthcoming with help!

To be honest my primary reason for liking the idea of the Cross Check was that it seemed more suited for touring, but that is based more on suppositions rather than facts/experience. The blades are thinner and look like they would absorb vibrations better due to the bend; and since I'm fitting narrow tires I just don't need a fork that's as wide as Surly's Karate Monkey or 1x1 - though whether the extra width (in terms of space between the blades) would have any actual drawbacks is a different matter. Am I on to something, or are my worries baseless - especially regarding "bent" forks being more absorptive than straight ones, despite having the same rake?

In any case, I've come over to the idea that I probably shouldn't mess with the crown-to-axle length too much.

I've seen the Thorn Mt. Tura (https://www.sjscycles.com/thornpdf/Th...aForkLoRes.pdf) mentioned a few times as just the kind of suspension-corrected touring fork that I'm after, and maybe it's not a bad option. I guess I have to make up my mind about whether it's worth spending almost twice as much for it as I would for the Karate Monkey. Any pointers?

M_S

The troll fork would work better for you. 5 cm less atc distance is too much I think.

https://surlybikes.com/parts/troll_fork/

As far as comfort, I don't know. That's not something you can tell by just looking at a fork. Maybe there are some other forks around which would be a better compromise...but I would sacrifice a tiny bit of compliance for proper handling any day.

Svet

Thanks! I think that one's for 26" wheels so the brakes won't be in the right place for my 700c's, but it's the right idea. I should probably try and find some advice on how riding quality differs for different fork shapes, but that probably belongs in a whole different thread (after a bit of googling). At least it seems I've got an unequivocal answer to my initial question: 50mm would be a ridiculous change .

Burton

Suggest you have a look at Kona forks. They have some of the best rigid forks on the market and they`re quite inexpensive. They cover road bikes, 29ers, 26in rigid, disk brakes or rim or both, and corrected for suspension or not.

M_S

Ah, wasn't aware you had rim brakes. I should have been though, since you were looking at the Xcheck fork, sorry. That makes things a bit tricky since lengthwise your current fork is similar to a 100 or 80mm 26er suspension fork but you're using 700c wheels. The karate monkey fork will be a little slacker (probably a similar length to your current fork when it is uncompressed).

BCRider

I'd keep looking around at 29'er rigid fork options. The 470 to 450 compressed reduction I can see. But dropping from a static sagged 450 to a rigid 400 is too big a lowering of the front. Your steering head angle will alter by more than I know I'd feel comfortable with doing. When it comes to steering head angles even a couple of degrees makes a big difference in how a bicycle feels for handling. And that much would also reduce the trail by quite a bit.

Mind you, often in model lineups the "cheaper" bikes using the same frame came with rigid forks that may well have been 400's or so and the "deluxe" models got longer suspension forks without much in the way of concern from the makers. So dropping the fork length to 400 to 420 may well be duplicating what the other models using that same frame had from the factory. Some more checking would be needed to confirm if such was the case.

SmallieBiggs

I, too, think the 2-1/2 to 3" drop might be a bit much - especially for touring, as it will make the bike's handling quite a bit quicker. The bike will likely still be quite ridable, but might be a little harder to ride no hands on rough surfaces.

I also agree with you, Svet, that the cross-check fork might have a more forgiving ride than some 29er forks like the Surly Karate Monkey model - curved blades and lighter weight seem to suggest this. However, the crosscheck fork is also shorter which could, in theory, make it more rigid. However, I doubt that will make too big of a difference. But the primary source of shok-absorbtion should not be your fork - it should be your tires. If you find your bike rides harshly, instlal slightly fatter tires and run them at slightly lower pressure.

Svet

Ok, it's pretty obvious that a drop of 450=>400 would not be a good idea - I've decided to definitely go for a suspension-corrected fork.

I spent some time looking through other discussions and there seems to be some consensus that on the whole curved forks are likely to be more compliant (/comfortable) than ones with straight blades:
https://forum.ctc.org.uk/viewtopic.ph...8902a2872ec74b
https://www.bikeforums.net/showthread...Straight-forks

Combining those two requirements, so far the only suspension-corrected curved ("traditional") fork I've come across is the Thorn Mt Tura (for 700c wheels with rim brakes anyway):
https://www.sjscycles.co.uk/thorn-mt-...ack-prod15586/
It looks kind of quirky (I can't really make up my mind about the double crown), though on the whole people seem to be pretty happy with it, so I think I'll loosen the purse strings and go with that one!

Bikedued

Whoa. That is one funky looking fork!.,,,,BD

SmallieBiggs

Are you sure this fork is for 700C wheels? The page calls 430mm the length of a 100mm travel fork, and that suggests to me that they are thinking about 26" wheels.

Svet

Yikes! SmallieBiggs, I think you just saved me what could've been a lot of hassle! I called to check and it is indeed 26". I did think that a crown-to-axle distance of 430 seems a bit too short for 100mm suspension, but didn't think it through properly as it was roughly the distance I was looking to go to. I guess I'll give up on the idea of getting a curved fork and revisit the straight Kona/Surly ones.

Svet

Ok, so it has transpired that I'm actually looking for a rather "exotic" fork...430-450mm axle-to-crown length, with v-brake studs for 700c wheels.

Suspension-corrected forks for 700c/29" (like the Karate Money) are generally too long because they're corrected for 80-100mm travel, and I've only got 50mm travel on my current fork. Meanwhile, forks for 26" wheels are closer to the right length, but have the brake bosses in the wrong place.

The only fork I've come across that looks right for me is the Tange Prestige 29":
https://www.ride-this.com/index.php/c...118-black.html
In fact it seems to be exactly what I'm looking for! I wasn't able to find a distributor that carries it in the UK, but I have a feeling that these "KF 700c Hybrid" forks might be more or less the same thing...
https://activesport.co.uk/shop/articl...-Steerer).html
I called a couple of online shops but none could tell me their axle-to-crown length (useless!) so I've emailed around...let's see.

In the meantime, here is a thread by someone who put a Cross Check on a hybrid that had an original geometry (450mm a-to-c) similar to mine - including pictures
https://www.bikeradar.com/forum/viewtopic.php?p=14830705

BCRider

Looking at my favourite shopping site I'm finding a few options. But some of them would require shifting to a disk front hub.

Disk only but 470 mm axle to crown ....
https://cgi.ebay.com/Niner-Rigid-Stee...item19c3c0bfc4

canti posts and 420 axle to crown. Still a hair short but better than 400
https://cgi.ebay.com/New-Uncut-1-1-8-...item2a0ec75dba

And this one is fairly cheap plus it has canti posts and from the link to the fork selector appears to be 465mm axle to crown if that's what "length" means.
https://cgi.ebay.com/eXotic-29er-Rigi...item2eb3611157