K2 / Proflex Riders Group

General => Tech Forum => Topic started by: SSSteve on November 09, 2014, 11:58:19 am

Title: Modifying a Crosslink fork for 29er
Post by: SSSteve on November 09, 2014, 11:58:19 am
Well I've been riding rigid single speed for a while, 29er, and really want to get my crosslink fork modded to fit the 29" wheel as well as disc brakes.
My rigid fork has an axle to crown of 470mm. I've read on here that the crosslink A/C is 430mm. I think I need to add 40mm from a donor leg(alu).??
Or make new legs?
Anybody done this?
Any advice?
Thanks.
Title: Re: Modifying a Crosslink fork for 29er
Post by: Colin on November 10, 2014, 07:23:34 am
"............................Any advice?........................

Yeh,.................... Good Luck!   <GRIN>

But seriously, welcome to the forum, we like adventurous (read "crazy") people!

Some people have converted their Crosslinks to disk, have a dig around on here, but I've not heard of a 29er conversion! You're treading fresh ground on that one!

But then again  I do run 700c Cyclocross wheels and road tyres on my Look Fournalles linkage forks, which do have the benefits of a disk mount and 29er clearance!

You're correct on the A/C on the crosslink being 430mm (ignoring headset) but the tyre clearance limit will be Axle to the Lower Link Axle Pivot Point or possibly the Lower Shock mount point "wrist Pin" Pivot (if that bottoms out on the tyre first during the suspension movement.)

I've measured that you have about 365mm from axle to Lower Link Axle Pivot Point on the standard fork.

As a 29er wheel is 622mm in diameter (311mm radius) that leaves you just 54mm (ish) for the tyre height, which I'd say is often about 45mm, so theoretically you might not have to lengthen the legs! but not much clearance! (anyone got a 29er wheel to offer up to a pair of Crosslinks?)

Good Luck! keep us informed and take piccies!

Col
Title: Re: Modifying a Crosslink fork for 29er
Post by: BikerTrash on November 10, 2014, 05:01:20 pm
I just tried to mount my 29er front wheel with a Kenda Small Block Eight 29x2.1 tire, and no go, not enough clearance. Looks like you'd need at least another inch in length to clear.
Title: Re: Modifying a Crosslink fork for 29er
Post by: SSSteve on November 11, 2014, 11:12:51 am
Thanks for the replies. Adding 40mm is about 1 3/4". Should give the clearance.
Since the legs just bolt on, I may just make / have made new legs, rather than cut up a vintage fork.

I found this pic from maybe 2001? Look at the lower legs you'll see additions welded in. This was before decent 29er suspension forks were available.
(http://i417.photobucket.com/albums/pp257/viking283/0F89949E-87D3-449B-AE7E-81C9037EACEB-837-0000009B937A2FF4_zpsbe6cc1ce.jpg)
Title: Re: Modifying a Crosslink fork for 29er
Post by: Spokes on November 11, 2014, 02:41:08 pm
That's interesting. One pair of legs would provide enough donor material to alter about ten forks? If the join was sleeved internally before welding it would be a strong joint. Possibly?? ??? The first big down hill would be very interesting!

Chris
Title: Re: Modifying a Crosslink fork for 29er
Post by: SSSteve on November 11, 2014, 03:53:30 pm
Yeah, sleeved for sure. But I don't know if I would trust it. Which is why I'm leaning towards making new legs with disc brake tabs.
I thought I would ask here, just in case that fork belongs to a board member.

Title: Re: Modifying a Crosslink fork for 29er
Post by: Spokes on November 12, 2014, 12:26:16 pm
I've not seen that before.

Chris