BMW Q6.S XTR rare folding bike

adilmon

Dirt Disciple
Hi all,
Just introducing myself. I recently picked up a rare BMW Q6.S XTR mainly because I like unusual stuff. Very similar to the Whyte PRST 1 front end, but with a few neat features. Partly going into detail because BMW are rubbish at publishing full specs and the below is a bit of a brain dump for future collectors or others interested in this bike. Some of the info may be an “afaik”

Produced since 1999 the Q6.S XT was later released as Q6.S XTR sometime in the early 2000s, which had some notable changes;
Frame: hardened Aluminium, with folding mechanism. Has “reaction free” rear frame by having pivot above the Bottom Bracket
Stem: ITM Millennium CNC aluminium
Seat post: ITM Millennium CNC aluminium
Flat Bars: ITM Millennium Ergal 7075 Ultra Lite
Wheels: Taurus Clincher 26” Rims
Front Hub: Quick release DT Swiss Hugi 240 (forged aluminium with sealed bearings) standard 100mm width
Rear Hub: Quick release DT Swiss Hugi 240 (forged aluminium with sealed bearings and ultra-reliable 18T patented star ratchet freewheel) standard 135mm width
Front Shock: Paioli shock 100mm travel, with remote rebound adjuster (on top tube)
Front Forks: These (like bmw motorcycles) are mainly only there to transmit steering forces. No damping or springs inside.
Rear Shock: Paioli shock 100mm travel, with rebound adjustment
Saddle: Selle Italia with BMW logo embroidered
Tyres: OEM fitment was Continental 26x2.1
Chain set: Shimano XTR
Cassette: Shimano XTR M953 : 9 speed (revised version with 5 rather than 4 spider supports) 12-34T
Derailleur: Shimano XTR RD-M953 Rapid Rise
Brakes: Magura Louise hydraulic disc brakes with 160mm rotors
Pedals: Shimano SPD PD-M545
Claimed weight: 28.5lbs or 12.9kg (will weigh it myself too)

With a huge price tag (£5,300 in japan, probably less in Europe), unconventional looks, BMW patented Telever front end and “only” 100mm of travel, the biking community was never going to be a hit with the masses. Nowadays it would be called a XC bike, whereas at the time I suspect longer travel, fatter adjustable conventional forks were more fashionable.

My plans for this bike are to turn it into a swiss-army knife of a bike (because who doesn’t love MacGyver?).
Hidden tools (Pedro’s Tulio Quick release multi-tool), pump (Topeak Ninja) and puncture repair kit all ready to install.
Mods are likely to be a stiffer spring for the front shock (will probably have to use a mini moto shock spring) and perhaps 54T star ratchet for the rear hub or integrated carbon bar/stem. Could easily mod to a 27.5”, but would probably need a 1.9” on the rear, so won’t bother.
Will share some pics in due course

If you’re still reading, this is the geek out bit:
I understand these bikes were made by Schauff bikes in Germany. A well-established family run German company that specialises in hand made bikes and tandems and they are the place to go should you need parts support (rather than BMW), although 20 years on I would have my fingers crossed. The only part I think are critical to be able to obtain is the lower ball joint on the front fork, although I’ve seen some well used examples still on the same joints and believe they’re likely over engineered. These threaded ball joints have a makers stamp on them (I later found out was an owl in a triangle) that I tracked down to being a LEMFÖRDER product (no luck sourcing from them as they make steering/suspension parts for vehicles and couldn’t reach the right person), so instead bought a whole fork assembly and front shock from Schauff just in case. I guess the fork may be assembled by Paioli, but tried contacting them but seems they’re more interested in motorcycles and scooters nowadays. These are made from unobtainium and I want to ride it without fear ruining a collectable bike.

Well done for reading this far, hope you found it interesting and useful for future peeps stumbling upon this.
 

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Cool, if unloved around here....I love a bit of weird suspension.

However, I only have the plastic model one off eBay:


All the best,
 

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Thanks. The models have more spares availability than the real thing(!)
It's ok, I like a cult bike or two.
Love the cannondale lefty, so much that I bought a folding bike version, the much overlooked Giant Halfway
 

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I also keep an eye out for the earlier BMW SuperTech, with the Sweet Spot URT back end.
file.php


There are some stupid asking prices on eBay for good examples,, but I'm not prepared to spend 1500+ Euros on one.
There was one for sale here a few years ago for £1000: http://www.retrobike.co.uk/forum/viewto ... p;t=354441

All the best,
 
Wow, that is gorgeous. Doesn't the BB being on the swim arm mean the suspension only works when sat down?
 
danson67":1k44q1k0 said:
I also keep an eye out for the earlier BMW SuperTech, with the Sweet Spot URT back end.
file.php


There are some stupid asking prices on eBay for good examples,, but I'm not prepared to spend 1500+ Euros on one.
There was one for sale here a few years ago for £1000: http://www.retrobike.co.uk/forum/viewto ... p;t=354441

All the best,


That looks like a cut and shut of my Schwinn - also a John Castellano “sweet spot” URT




adilmon":1k44q1k0 said:
Wow, that is gorgeous. Doesn't the BB being on the swim arm mean the suspension only works when sat down?

Your right, makes it great for climbing kinda close to a hardtail
 

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Re:

Well, i dont think ive ever seen one of those before, I can see the similarities in the suspension design eith the Whyte PRST bikes. Like you say, probably best to have a back up of spares if you want to continue riding the bike, it looks like it could be fun to ride!
And that Giant Halfway is truly "different" :shock: :D
 
It certainly does travel more when sat down, but the John Castellano designed it that way.

Back in 1994/5, when it was designed, XC riding was king, not all that ridiculous downhill malarkey.
The 'Sweet Spot' was designed to give 100% travel when riding seated, some travel when standing (about 70%), but a rigid feel (about 25%) when climbing.
Also eliminated loads of the pivot, gear change and pedal bob problems found in single and multiple pivot suspension systems of the time.

Here's the blurb for the Ibis Szazbo, which used the pivot design, also seen on the Breezer Twister, Schwinn Homegrown, Control Tech, Catamount


All the best,
 

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Just triple checked and the Q6.S isn't a URT, with a swing arm pivot just over the BB.

Working on some mods that will probably please nobody other myself:
Rear Shock
Sourced a 165mm Fox Factory Float rear shock. Nice bronze kashimi coated one that I can pump up to my weight. Was going to buy a new DNM one, but decided would be a false economy compared to a rebuild-able Fox unit

Front Shock
The front shock clearance in the frame is tight at 45mm (current shock is 39mm at widest Outer Diameter, 120mm Spring free length, compresses to 70mm, with 28mm spring inner diameter surrounding a 1" diameter gas cylinder). So in touch with a company that makes custom springs. Calculated the front shock spring with current 5.5mm spring wire gives spring rate of 200lbsf/in. The custom spring that respects the clearances is 41mm OD and 6.5mm spring wire (1mm thicker), giving a spring rate of 350lbsf/in, which would be a great improvement.

Rims
I also have a set of unique motorcycle trials inspired rims that in process of sourcing. Will reveal more soon...
 
Re:

The wheels have been bought... they're crank brothers 26" tubeless (no spoke holes in the rim)
I wanted a pair of Cobalt 2, but could only find a front, however got a higher strength Iodine 2 for the rear.
Did my homework- they've adapters available to cater for old QR or later standards. The reliability of older versions was sorted. Will still probably run them with Slime's pre-filled tubes because life is too short.

Also fitted a double bottle adapter to the top tube mount. Lots of room and makes the rebound adjuster more accessible.

Gold KMC chain waiting to go on.

Now to think about the low stem. Do I fit an adjustable one or fit a steerer tube extender?

This is turning into the my ultimate noughties XC

Do I want to follow the trend of going 1x ? Nope thanks.
 
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