Custom 650B dropouts for Marin Quad Link 2 bikes

Would like to gauge some interest here for a possible run of custom dropouts that would move the wheel back approx. 12-13mm and allow better fitment of 650B wheels for these bikes. Mostly no contact with seat post at bottom out and FD interference, adds some wheel base which aids climbing and keeping the front end down (most Quad Link bikes have somewhat short WB IMO) and a little more stability. Would hopefully allow the use of the tallest 650B tires available without any shock shimming.

These would fit 2007?-2011 Quad Link 2 bikes (Rift Zone, Mount Vision, Wolfe Ridge, Attack Trail, etc)

135×12 or better 142×12 possibilities (no wimpy std. QR) Hopefully a replaceable hanger so the entire dropout doesn’t need to be replaced.

Thoughts people (or maybe it’s been done already?)…and what are you willing to pay for such an item like this?

Aren’t these a touch high in BB height with a 26″ wheel and normal ish tyre?
Upping to 650b wheel, fork and fattest tyres available aren’t exactly going to help out the BB height?

Is there space in the frame, design and production scope for a new set of swingarm rocker’s made up that would aim to drop the frames BB height a fair bit to offset the 650b height changes?

Presuming the dropout braking wear problem would still be present? ie where the dropouts vibrate/rock about under braking once it wears over time?

@James

As the owner of an ’09 Wolf Ridge (and an ’08 Rock Springs if you include the missus’ bike) then I can put you right on the misconception that these have a high BB. They’re pretty low, certainly they’re on a par with the Camber that’s parked in my garage right now that has a supposedly low BB.

Having said that, the fact that there’s a chunk of aluminium bolted to the back of the swingarm gives some leeway in axle – and therefore BB – placement, so any increase in static BB height could be minimized, at the expense of slackening the head angle a degree or so, given that you’ll raise the front end a little even if you opt for forks with a low axle to crown height.

The linkages themselves dictate the feel and progression of the suspension. I know that the ’09 Attack Trail which was equipped with a Hammerschmidt crank required a reprofiled lower link to help deal with the pedal bob, but the outcome of changing the design of the links themselves is most likely going to be some frame clearance issues and the loss of the reactive pedal feel – not to mention ruining the feel of the shock too unless it’s retuned to suit.

If you were going to alter the geometry of the Quad Link II frame, then working with the dropouts would seem by far the easiest route to me.

I’m actually in the North East USA and where I ride it’s extremely rocky and technical. My ideal BB height is approx 13.75″ (350mm) with 13.5″ (343mm) about as low as I can live with and up to 14″ (355mm) ok. My converted 650B Prophet has a 14.25″ BB height which is really to high IMO but I’ve lived with it and you adjust.

New 650B dropouts for the Quad Link bikes could have the axle moved just straight back (then the BB would be approx 1/2″+ higher or 13+mm with 650B wheels) or the axle could be raised slightly in the drops to either keep the same original BB height or something in between. Doesn’t take much but since I’m driving this idea I want the BB height to go up a bit over stock. The love affair some people and companies have with low BB height I just don’t get for a trail bike you ride everywhere. I hate pedal strikes and yes my technique is just fine. I’ve got a vendor lined up to do these but not as just a one off piece. They would like to do a small production run if the interest is there to justify the time/expense. 6 people and counting on MTBR have expressed interest but Europe seemed a more popular market for the Marin bikes so I’m asking here also. All ideas appreciated.

Messing with the quad links is not something I would even consider doing.

…adds some wheel base which aids climbing and keeping the front end down (most Quad Link bikes have somewhat short WB IMO) and a little more stability.

Thinking about it, the WR does have a very short rear end, I can’t help feeling that a little more length in the wheelbase wouldn’t go amiss.

I’d be interested!

I’d be interested 135×12 maxle pair or two.

If you are thinking of making the mech hanger replaceable please make it strong! I have yet to bend a maxle, non-replaceable mech hanger or a rear mech……….replaceable mech hangers on the other hand….countless 😡