Altitudally challenged (aka short) riders... need some input

[S.]

I was just thinking about how shorter riders cope with dual suspension bikes (for DH - XC bikes are another matter)... do you guys have difficulty finding a frame small enough at a reasonable pricepoint? I know I suggested BB7s and 222s in another thread, but they cost a helluva lot...

I'm 6'2" and haven't ever had trouble finding a bike to fit me, but I imagine anyone under 5'8"ish would have trouble finding bashworthy bikes that are small enough and affordable?

For anyone who fits into this "altitudally challenged" category, what problems do you have with the geometry of your current bike (duallies only please - there are more than enough tiny hardtails to go around)? Do you find the standover too high? Top tube/chainstays too long? Too much/not enough travel? Too slack/too steep headangle?

Give me your thoughts... (NOW).

 

[bazza]

imagine that

no offence to little people but imagine one trying to get on the old norcos, they would need a ladder to get there. even i have to put a bit of a jump into it!! and theres are only the medium ones and im 176cm.

 

[mtbdh_girl]

hey socket,

Im about 5'8. I know its different again as far as height probs for boys and girls. my biggest prob is always standover height. theres not that may small size frames around, and even some of those i still struggle.

Riding your norco with the seat at its lowest i couldnt touch the ground sitting on the seat, and could only just touch the ground when standing over the frame...

anyways, best small bike ive ridden was an orange, it was funny though cos the weight didn't really bother me...

 

[ELX]

I'm 13 and 142cm or around 4'6 - 4'8. In other words short. I'v dont have i dually but i have an 18 inch HT. I founf the overall length to big when i first got it but now after I have moved the seat forward and bought a shorter stem. I dont have any problems, i also dont have any problems with the standover hieight and i can eaisly get on. I used to have a 20" BMX so it was quite a change to go to the 26 MTB but i am used to it now and i run the seat fully low because it's more comfortable. So in answer to your question no i dont really have any trouble with the size of my bike.

 

[S.]

I'm 13 and 142cm or around 4'6 - 4'8. In other words short. I'v dont have i dually but i have an 18 inch HT. I founf the overall length to big when i first got it but now after I have moved the seat forward and bought a shorter stem. I dont have any problems, i also dont have any problems with the standover hieight and i can eaisly get on. I used to have a 20" BMX so it was quite a change to go to the 26 MTB but i am used to it now and i run the seat fully low because it's more comfortable. So in answer to your question no i dont really have any trouble with the size of my bike.

duallies only please - there are more than enough tiny hardtails to go around

Cindie: So you reckon most frames are too high for you? Do you have any problems with chainstay or top tube length?

 

[S.]

Here's something I whipped up in linkage/MS Paint in about 10 minutes... Aside from the minor problem with chain routing through the isolated link (it could cause a fair bit of slap), it has a nice rising rate, reasonably low pivot for low pedal kickback but high and forward enough that the axle doesn't curve forward too much... and as you can see from this pic, it has plenty of standover! You could run the seat barely higher than the rear wheel (just hafta be careful of the tyre hitting the seat or seat tube tho I guess).

Just my attempt to see if a reasonable linkage bike could be made small enough for smaller riders... what do ya think?

 

[inlina]

I reckon that there is a niche in the market there Socket. Dirtworks in the states has explored it, with the bike Tai Lee was on last year. The biggest problem for everyone out there making frames is whether the market is big enough.

For the few small sizes that are out there the top tube is also useually shorthened relative to the frame size adequately. I don't quite see how the chainstay length will affect a short rider too much? Enlighten me??

The Raceline DH bike was/is available in quite a small frame, we are thinking about getting a 2nd hand one for Cindie (and Raceline seemed to struggle to comprehend that they didn't sell any because the package wasn't up to spec).

The other consideration that people who are making frames that they either look over, or don't want to consider, is that on average (OK it's not a perfect assumption) smaller people are also lighter (and chicks are weaker), therefore don't needs 7+ inches of travel at both ends.

Hell, there are so many design parameters that these 'designers' get wrong/overlook at bike companies, that it's a wonder that they come up with a saleable design.

Hey, here's an idea for a new thread - 'Why do all my posts turn into bitch sessions?'

CG

 

[S.]

Chainstay length affects the stability of the bike, and how easily it manuals, bunnyhops and generally sits on the back wheel. Longer stays = more stable (think V10), shorter stays = more flickable and easier to get the front up (eg your typical street/jump hardtail). As you said, smaller riders often aren't as strong as 7' tall monsters, so the added ease of maneuvrability could be useful.
A shorter top tube (19" or less maybe) would definitely have to be on the cards.

What would you consider the ideal amount of travel at each end for a smaller person's bike? (the bike in the pic has a theoretical 200mm/8" with a 2.75" stroke shock, I could quite easily shorten the travel AND ramp the rate up)

 

[SpectRe]

Yeah - theres a Jamis bike i saw a chick riding at the nationals in thredbo - it was sooooo tiny!
It wasnt a full blown DH rig, but it had boxxer races and looked to have around 6inches of travel or so.
A bike like that would be ideal for the smaller rider - HEAPS of standover height. Might have to find a pic somewhere - unless of course someone beats me to it.

 

[S.]

Yeah - theres a Jamis bike i saw a chick riding at the nationals in thredbo - it was sooooo tiny!
It wasnt a full blown DH rig, but it had boxxer races and looked to have around 6inches of travel or so.
A bike like that would be ideal for the smaller rider - HEAPS of standover height. Might have to find a pic somewhere - unless of course someone beats me to it.

Did the chick riding it have bright red hair? I think that's Amanda (dunno her surname)...

 

[inlina]

Socket, is the green bit in your picture 1 link or 2 (the first time i looked it appeared to be 2, but now it looks like one...aaahh, you're freakin me out). If it's 2, your Gruebler count show 2 degrees of freedom (if it's one then it's cool).

I have a design that shorthen's the chainstay length to be pretty much a hardtail length, and could still run up to (and maybe more than) 9" of rear travel. However, that stay close to my heart until I get to patent time (I won't even tell Cindie, but that's cause I don't want to spend 10 hours running through CAD data and animations trying to explain it to her).

I think the fundamental problem at the moment facing 'designers' in this sport at the moment is that they don't have the ability to think/visualise outside the box.

EG running 'The Brain' on an FSR linkage is such a waste of weight. Obviously, the design brief proforma at Specialized says:
'Rear Suspension - FSR 4-Bar linkage, cause we spent a shitload of money on the patent, and were gunna get our moneys worth out of it.'

CG

 

[Ty]

just an idea before i go to bed, since your scaleing down the TT and stays and trying to get a better standover why don't you design the bike around 24 inch wheels?

 

[inlina]

So long as this 24" bike won't be raced at a UCI event (unless there has been a recent rule change) then it'd be OK.

I only skimmed the rules, but the UCI define a mountain bike as having 26" wheels and at least 6 speeds (although it may have changed since, but someone re-iterated it to me at a club meeting).

 

[inlina]

So long as this 24" bike won't be raced at a UCI event (unless there has been a recent rule change) then it'd be OK.

I only skimmed the rules, but the UCI define a mountain bike as having 26" wheels and at least 6 speeds (although it may have changed since, but someone re-iterated it to me at a club meeting).

No, actually, I'm wrong. Only real rule governing this is wheels may be no bigger 26". So I can ride Cindie's freestyle bike at World Cup this year, those bastards led me astray. Maybe it's in the MTBA rules??

 

[Stinky]

Yeah that is still the rule, thats why the top trials riders have a special cassette made up with four carbon fibre cogs. You wouldn't want to put any power through them but they meet the rules.

Socket, with all of the shortening of the tt and stays, would that rig still be stable at high speeds or would you need to run a really slack head angle.

 

[Gutty]

I ride a 16" and thats only just small enough for me as far standover and top tube length go(i wish it was a 15") but i'd actually like the chainstays to be a touch longer to help keep the wheelbase somewhat reasonable for DH applications. Though my bike does have quite a steep head angle and if that was a bit slacker maybe the chainstay length would fine as is...........ah...i dunno.
I like the look of your design Socket, though what kinda loads do you expect around the linkage area ? It looks very RMesque.

BTW, i'm not quite 5'7"

 

[Simo]

as you know socket im a smidget (small midget) and ride my stab (well, some times)
The only complaint's i have are:
If i step off my manhood gets crushed on the top-tube
and
i suk at mono's (my fault, but y not try and blame the bike )

also, horses tend to think you're a meal (see post "ouch" in off topic)

 

[S.]

Socket, is the green bit in your picture 1 link or 2 (the first time i looked it appeared to be 2, but now it looks like one...aaahh, you're freakin me out). If it's 2, your Gruebler count show 2 degrees of freedom (if it's one then it's cool).

I have a design that shorthen's the chainstay length to be pretty much a hardtail length, and could still run up to (and maybe more than) 9" of rear travel. However, that stay close to my heart until I get to patent time (I won't even tell Cindie, but that's cause I don't want to spend 10 hours running through CAD data and animations trying to explain it to her).

I think the fundamental problem at the moment facing 'designers' in this sport at the moment is that they don't have the ability to think/visualise outside the box.

EG running 'The Brain' on an FSR linkage is such a waste of weight. Obviously, the design brief proforma at Specialized says:
'Rear Suspension - FSR 4-Bar linkage, cause we spent a shitload of money on the patent, and were gunna get our moneys worth out of it.'

CG

The chainstay (dark green bit) is one piece. I know it looks like two but it's one, the aqua-coloured bit is the isolated link.

I can't wait to see your design (one day). The problem with trying to keep stays that short is that you have to avoid the seat tube, and at any rate (unless you have the CC as the BB, in which case the tyre will hit the seat tube) you're going to get a virtual chainstay extension/compression anyway. Stays could be made sub 14" (on hardtails) by using elevated stays (Gack or Goat or someone has tried this), but they're just TOO short then.

Gutty, the loads on the link wouldn't actually be too bad I think. It's not much more than a 2:1 lever (as opposed to say an RM7 which is about an 8:1!). Turners have a higher leverage ratio (on the pivots, not the shock) than on that pic I showed.

Ty: I had considered making it 24" specific, but I don't really like that limitation (eg BigHits), and I can't think of many decent but light 24" rims, and tyre choice is more restricted. What I had considered though, was having a 1" adjustable axle position that could allow the running of 24" only in one position, and 26 OR 24 in the other. But yes, it's a thought.

Tonight I'll put up some pics of some quick linkage sketches and what their potential benefits could be.

 

[felix]

i know ur lookin at duallies but the 1 thing that i noticed about my fischer hardtail frame 13.5 is that the bottom bracket height is shorter than the ones on other people's bigger framed bikes, i'm guessin it's to do with the overall geometry

thought that mite give u some extra info u could use?

 

[S.]

Socket, with all of the shortening of the tt and stays, would that rig still be stable at high speeds or would you need to run a really slack head angle.

Stability is relative IMO. A short rider will find that they can't throw a big bike around enough (ie it's too stable) and a big rider may find small bikes to move around too easily (not stable enough). For example, try riding a tiny little jump bike down a DH course, then put a little kid on the same bike and ask them if it feels too twitchy.

Felix: are you comparing your frame to other larger sized frames of the same model? If not, it may be just something to do with that model, completely unrelated to the size of the frame.