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.

for some strange inexplicable reason i like that

Yeah, it's definitely a 'looks so wrong it's right' sort of thing.

i think it must appeal to the minimalist in me

I agree it wasnt worth spending the extra on it for gears..

Your both weird. 😉

I like it too.

Is it just me or does it look like it's made of Lego?

Thought my saddle looked high… 😉

Its so bad I had to back for another look, now I have noticed the massive seatpost, so you waited 15+ years to get one and you bought one a bit small for you, then with all that height on the saddle you thought nah I dont need to put the spacers under the stem, I will keep that nice and low!!

It looks really, really uncomfy!

I just dont think its for me, and I like quirky stuff.

Shows how much you know 😉

Because it's a URT, it settles down, reducing the saddle height and making the bars the right height relative to them… Same reason that the saddle points down slightly in the pic with no rider on it.

The seatpost is only a 367mm one. The seat tube is only reamed for about 10cm so any longer seatpost in the frame makes no difference.

That's not to say it doesn't look odd.

(FWIW, this is my usual SS and the Mantra pretty much feels the same position-wise)

ever since seeing BP's bumble bee I have REALLY wanted one. When I have oodles of money and space I will have one just like that, or maybe the carbon one hmmm.

Looks very right to me.

I always thought it was pig ugly. Their other bikes (thinking about the Adroit) though were things of beauty.

I used to have 2 orange urt bikes, i cut them up for a GCSE project

Those oranges were horrible though – heavy as a truck! The Mantra built up with the same kit barely feels any heavier than the 853 on-one above.

very true, i remember berating orange at a bingley race about how crap their designs were.

mmm Nightstorm

Jeezus wept clubber, you really are the Steptoe of the MTB world.

😉

mmmm snowflake wheels. very retro

Never did see that film, KT so you'll have to explain that to me…

@ Clubber. Like that Klein!! Is an always will be a strange looker though. Will it be making the SECC 10?

Yeah, I think I'll take it to SSEC though based on Saturday I prefer the on-one so I might take both frames, ride the Klein for some of it and the on-one for the 'race'.

It's getting replainted though – got the Gold Klein stickers on the way. Purple paint ahoy!

Steptoe and son were rag and bone…oh never mind..

I own a 1999 Mantra Pro and was thinking of doing something similar. I am going to be a SSEC10 also… would it be possible to get a test ride to see if I like it?

I don't know if you know this, but the bike was originally designed by Gary to have a rigid fork.

How did you get round the headset issue with the mantra? I thought they were all made to take a 1 5/16" stems and tapered steerers?

There was a Mantra-like Klein with the rigid front, anybody remembers the name (I haven't got the catalogue any more, sadly)?

I understood the priniciple of these bikes, but the issue i had is that unless you were sat down with very little weight on the bars, all the shock would be transferred directly throuigh your arms anyway before the 'suspension' had a chance to absorb it

nice experimentation though!

Holy thread-ressurection!

pkcain – Member
I own a 1999 Mantra Pro and was thinking of doing something similar. I am going to be a SSEC10 also… would it be possible to get a test ride to see if I like it?

I don't know if you know this, but the bike was originally designed by Gary to have a rigid fork.

If I have time to get it together and up there then yes (I'll actually be riding my inbred for the 'race' but will probably take the Mantra up to ride on one of the other rides

Yep, I did know – that's why I fancied trying it.

skidsareforkids – Member
How did you get round the headset issue with the mantra? I thought they were all made to take a 1 5/16" stems and tapered steerers?

Mine's a comp so it's just a standard 1 1/8" headset

Tim – Member
I understood the priniciple of these bikes, but the issue i had is that unless you were sat down with very little weight on the bars, all the shock would be transferred directly throuigh your arms anyway before the 'suspension' had a chance to absorb it

nice experimentation though!

You're pretty much right on that actually but I still fancied trying it to see what it was like. Switching back to the inbred (just swapping the frame so everything else is the same), it was noticeable though that everything did just feel bumpier – even at the front end so there clearly was some effect.

Cool, it would be great to check it out.

I'm actually considering putting the 425" fork on with a 29" front wheel. You'd get benefits from the larger wheel and the geometry would be mostly unchanged.

I was using a 440 fork which is a touch long I reckon – the 420 would be ideal.

Would a 29" wheel fit in a 425 fork? Irrespective don't forget that while the head angle may be unchanged (ish), the trail will be due to the bigger wheel which will slacken the steering.

According to the White Brothers (same as Exotic) website, the 425 fork will fit a 29" wheel. I'd be surprised if the change to the trail would be that significant. I'll have to check into it.

Given the bars don't move relative to the front wheel, how anyone thought this might have "front suspension" is beyond me.

Agreed and yet it does seem to have *some* effect.