P2 29ER FORKS?? ON A 91 CINDER CONE....?

[tee-one]

Was mooching around various sites the other night looking for fork ideas for my cinder cone.

And found a page that mentioned using 29er forks...

Thing is, Appart from them being taller. Wouldnt the canti mounts be totally useless?

anyone done this? Im finding it near on impossible to source some 26" p2's with a 220mm steerer.... :?

That and im worried about the rake it might give the frame.. Old kona frames IMHO lean back about as far as i find acceptable allready. Without the help of a long fork...

 

[markoc]

This would most likely murder the geometry and handling. See all the threads about putting 80+mm travel forks on retro non suspension corrected frames. Your headtube would be taller/higher than it should be, which would make things interesting and possibly put more stress on the frame (but I'm no expert on engineery things)

 

[DM]

I have 90s Konas and suspension-corrected 29ers.
The forks are totally different lengths, so I wouldn't advise swapping them.

How long is the steerer on a new P2?

 

[Anthony]

Your frame is built for a 39cm a-c P2, so even a 94-onwards 41cm a-c P2 would slacken off the head angle. The a-c of the 700c/29er P2 that Chain Reaction are selling is somehow quoted at only 40cm, so I can only assume that it must work only with narrow tyres. However as you say the brake bosses will work only with a 700c wheel.

This type http://www.retrobike.co.uk/forum/viewto ... highlight= has a 47cm a-c and can obviously take any kind of tyre, but a 47cm a-c would be way too much for your frame.

If you fitted a 700c wheel, even though the a-c of the CR fork was ok, the greater radius of the wheel would raise the front end by c3-4cm, reducing the head angle. Plus the bigger wheel also makes for slower steering (hence 29er frames usually have a steeper head angle, not a slack one).

I think your best bet for a 91 frame, is either to stay with threaded and look for a period 39cm P2, or to fit a 94-onwards P2 and speed up the handling by using a shorter stem.

 

[DM]

The a-c of the 700c/29er P2 that Chain Reaction are selling is somehow quoted at only 40cm, so I can only assume that it must work only with narrow tyres. However as you say the brake bosses will work only with a 700c wheel.

Oh, THAT one. I guess it was from the cyclocross bikes or the 700c hybrids. I think mine was about 395mm A–C, so it's in the ballpark of a 90s 26-inch fork.

Brake bosses will be positioned wrong for 26-inch wheels, but a disk mount (if any) would obviously work.

Everything Anthony mentioned about the handling and geometry is correct: I tried a narrow 700c wheel and 700C P2 on a 26-inch Kona and it sucked. And caused toe-overlap.

 

[We_are_Stevo]

Being first and foremost a m'cyclist who started out in the Seventies on a Fizzie and grew up on 'Easy Rider' and the like I find a certain degree of amusement at the bleating over fitting a fork that is only a few cm's longer than OEM

If you want to fit a longer fork then try it; if you like the way it looks and you can ride it then where is the argument?

If Chas Roberts says you can fit a 100mm fork to a D.O.G.s' that originally had an 80mm then there's no reason why you shouldn't experiment with your own fork choice at home;


The two important dimensions are the rake (head tube angle) and trail (a measurement on the ground taken from a vertical line through the wheel spindle and a line from the fork); the longer the line on the ground (trail - so called because the vertical line from the spindle trails behind the point where the line from the fork meets the ground...) the slower the steering.

If you transfer the physical measurements from your bike to paper in a drawing you will see you'd have to fit a seriously long fork before you start compromising the performance of you bike!

 

[13]

yea i think anything to do with 29ers is a bad idea, be patient ebay is your friend

 

[We_are_Stevo]

...and I really, really don't understand the reluctance to make use of the readily available steerer extenders that make fitting any fork to any frame so painless??

 

[Andy R]

If you fitted a 700c wheel, even though the a-c of the CR fork was ok, the greater radius of the wheel would raise the front end by c3-4cm, reducing the head angle. Plus the bigger wheel also makes for slower steering (hence 29er frames usually have a steeper head angle, not a slack one).

Or they have forks with something like 55mm of offset, as opposed to the more "normal" 38mm offset. This reduces the trail and therefore counteracts any tendency for the larger wheel to slow the steering response (this has more to do with the increase in the trail figure that the larger wheel radius causes than any other reason). The greater fork offset also reduces the tendency to toe overlap, especially on smaller frames, which would otherwise have a shorter front centre.

 

[tee-one]

...and I really, really don't understand the reluctance to make use of the readily available steerer extenders that make fitting any fork to any frame so painless??

that's an interesting Lil bugger. Hadn't seen one of those before.
That might give me the option to run a set of those p2 forks that pop up on eBay with short steerers .

You used one of these before?

Hadn't realised so much goes into choosing the right fork....Cheers very Much for the advice guys....