Klein Mantra (sweetspot URT) with a rigid fork - feedback

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I've seen a few discussions over the years about Sweetspot design URTs on here and other forums. An interesting idea was the way that they were originally designed to run a rigid fork, the theory being that with the pivot being very central on the frame, it would work for impacts on either the front or back so you didn't need a suspension fork. Aparently marketing (eg people didn't like the idea of a suspension frame with a rigid fork, at least not by the mid to late 90s, I know that sus frame and flex stem was used before that but...) meant that they ended up selling it with a suspension fork.

Anyway, I recently got hold of a bargin Klein Mantra as I always fancied trying it out. So, built up as pictured (SS'd), I ventured out and found that... well, it rides like a rear sus frame with a rigid fork :) I guess that the imbalance in weight/loading between front and rear means that the front 'suspension' is much too stiff to be very effective though it did feel a little (and I mean just a little) softer than a normal rigid front end. It'd be interesting if the pivot was further back to give the front more leverage (eg making it softer) but that's obviously not going to happen.

Anyway, I'll give it a few more rides to see but then may well fit some short suspension forks.

As to the URT aspects of it, I was pleasantly suprised actually. Having ridden some URTs when they were actually seen as the holy grail (a very short period in the mid to late 90s admittedly), I expected it to feel pretty bouncy and also markedly different in and out of the saddle. As it was, the pedalling seemed quite stable (but it's got a modern Fox Float R shock with propedal which undoubtedly helps) and the difference in suspension action in and out of the saddle didn't seem too extreme though I had it run with little sag just to avoid too much 'jack' on braking.

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Snap :)

Found mine to ride a lot nicer witht he rigid for rather than a suspension fork, guess that could have just been the fact I prefer rigid forks anyway or maybe the fork I used to have on it was always too soft. Certainly made climbing a lot easier

Will be interested to see what you think of it after a few more rides
 

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I can't believe that it works with a rigid fork - the unsprung weight would include the frame and the rider's weight on the bars. :?

..whereas with a sus fork it would just be the front wheel and fork lowers.
 
Thats funny without seeing your comment Hamster ... I just said the same thing to myself ...Dont make any sense to me
 
Think it's one of those things that you need to ride to understand

Mantras are the weirdest things to ride at times, basically forget anything you thought you knew about downhilling on them

They have a real tendency to "jack knife", they shorten the wheelbase by 3" just like that :shock:
 

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