Ventana 29er Hacked with Gates Belt Drive & Shimano Alfine Di2

Sounds to me like the problem was physically with the hub and fitting it, not a problem with the electronics and getting it to actually shift, but I could be wrong.

Where is the frame break? I don’t see an s&s coupler or anything else…

The frame breaks @ the dropout.

I too had to look very closely at the picture to see how the belt when on, wish you would have explained it a little more

@Nicolas — Yes, plenty of belt drive Alfine bikes out there, but how many with the new Di2 Alfine electronic shifting?

@Dave…that doesn’t look to be DI2 Alfine.

Increased reliability by using a belt drive and IGH.
Then reduce reliability (and cause incredible amount of hassle getting it to fit) by using electronic shifting.

WHY??

Why not just Alfine 11 mechanical and belt?

To bring everyone up to speed on why this is hard…..

Firstly the frame has to have a split in the stays for the belt to pass through. I’m not sure if the ventanna does have one, but I have seen mods.

Secondly making an Alfine work on a Mtb is a huge challenge! The issue being chain (belt) alignment and clearance of big tyres. Te belt has to have a certually straight, which is not an issue on city bikes as the tyres are not wide an do not rub on belt. On a wider tyre for Mtb, it forces te belt out further from the frame. This is typically not an issue on single speeds belt drives as you can change rear belt line on rear hub through use of spacers (or by using a specifically designed frame, single speed hub and crank with correct alignment). On the Alfine however, due to the shifting mech on the outside of hub, the cog is located a long way toward the centre of hub, meanin if you go for correct belt line, the belt fouls on the wide Mtb tyre.

I would be interested in seeing the mods they have done to the rear cog to make this work. I know one of the custom frame builders was making an offset gates rear cog to make this work.

Cool mod!

^^ how many people have broken a belt? Given the industrial and automotive applications for those belts, I would feel perfectly safe with no spare on a bike.

For an update on the status of the belted DI29er, check out http://www.cyclepathnw.com. Nelson’s been beating this bike down and it’s holding up like a champ! We should note, this build utilizes the centerline belt and cog system from Gates, not the original belt/cog design that slipped like mad.

Frame-break askers… the dropout looks to be completely disconnectable, easily visible in the first two pics. This guy is a complete hammerhead, so trust the claims of no slippage.

We have had many people email us asking for step-by-step directions on how to do this conversion. Many of them have been unhappy when we opt to not share the knowledge. I figured we’d give some insight as to our decision:

we spent more than three days working out this special build. I paid over three days of wages for several people not to mention the expense of all our shop resources. It was an awesome feat that we wanted to give up on several times because of all the intricacies and dead-ends we hit. Both Shimano and Gates said it couldnt be done. This was to be a showpiece for our shop. Shimano emailed us right after this article hit asking for photos and step by step tips. Much as they dont share their trademark secrets when they develop a product, we werent going to give our hard work and expenses away for free. What we did was very technical and would require the use of a machinist to do it right. So, its not something we’d want to put out for the general public to try. It’d be a recipe for disaster, especially considering the lengths we went to voided any and all warranties to the products we altered. We are happy to make this conversion a reality for others at this point, but it will come at a cost equal to the effort put into it. This next time around it wont take anywhere close to the same amount of time, but there are things out of our hands that can make or break the success of the project outside of the conversion itself (ie: chainline of a given frame. crank vs frame compatibility. etc). These are further reasons this task is best left to your professional bike shop.

Please post some updates, how is the bike handling ? Have you had any problems ?