riceowls

I found a good deal locally on a 2012 Co-Motion speedster with Spineryand bought it as an upgrade to our current T2000 Trek. The drivetrain looks very good (very little use of the bike per owner), but I'm definitely taking it for tune-up/lube all over. I am considering a few upgrades going forward and can use some input:
1) Gravel wheels - what is the max tire size clearance on the bike allows? Is purchasing/building 650 gravel wheelsets possible to allow 40mm tires?
2) Is the Gate drive timing belt upgrade worth it?


Anything else I should consider?

reburns

Congrats, that looks like a great find. I have a 2005 Speedster I bought in 2016. That was before they went to disc brakes, so the frame clearances may be different, but on ours the seatstay clearance is 44 mm, meaning a 38mm actual width tire will have 3mm clearance either side. I have a 700x38mm specified tire on the rear at the moment that actually measures at 40.5mm, which is really marginal for peace of mind but working okay otherwise.

I made a lot of upgrades to our Speedster, including Spinergy wheels, timing belt, carbon fiber handlebars and stoker stem (it already had CF cranks and fork) and suspension captains stem and stoker seatpost. It is a really comfortable yet efficient bike. Handles intuitively.

I recommend the Gates belt. Clean, quiet, no maintenance. Pretty easy retrofit and not that expensive.

TobyGadd

The Gates belt is absolutely worth it! Especially if you ride a lot, you'll appreciate not having to re-tension it like a chain requires. Nice and clean as well. Just make sure that you don't forget to pull and lube the eccentric once a year or so anyway to keep it from seizing up.

I also recommend a Thudbuster eeSilk seatpost for your stoker. Since stokers can't easily see approaching bumps, they can't subconsciously adjust their bodies to absorb/deflect them--making for an uncomfortable ride. The eeSilk has the least bob & bounce of the 4 different posts that we tried, while still soaking up some pretty big hits. Especially important if you're going to be riding any gravel.

bboy314

Since you’re in Houston, check out https://www.houseoftandems.com if you haven’t already. Very helpful folks.

We have a 2010 Speedster, pre disc brakes (though the frame has the option but not the stock fork). Room for knobby 700 x 35 on ours. I have considered building 650b wheels for it but haven’t done so yet.

Paul J

Our Speedster is a couple of years newer but the same frame. We have added the belt drive which is great. We've never run anything larger than 35c which works fine. I too have wondered about 650 size too. I remember Co-Motion telling someone else that they shouldn't do it but at worst it would lower the bottom brackets a bit which could cause pedal strikes, but probably not. Keep us posted on your progress.

riceowls

what's the advantages of the belt upgrade that you've noticed? As for teh wheels, I am currently thinking about getting 148mm thru-axle wheel and adapting it for the 145mm. I will let you know if that works.

merlinextraligh

As mentioned by others above, the belt is clean, quiet, very rarely needs adjusting, and lasts longer. We have belts on 2 Calfees, and have at least 20,000 miles and 10,000 on the belts.

An advantage that hasn’t been mentioned is a more immediate feedback between the captain and stoker. We’ve found that the stoker can feel more what’s going on and what pedaling effort is needed through the belt than with a chain which is just a bit sloppier.

Riding in a group, or pace line, this is actually a significant advantage in modulating effort to maintain position. My stoker can feel when we need to soft pedal to be smooth in the line,and when we need a touch more effort to avoid a gap opening.

Also, the belt system is going to save you about 10 ounces over a timing chain and cogs.

merlinextraligh

In theory, 650b wheels with wider tires shouldn’t lower your BB, if you go with a sufficiently wide tire. The diameter of 650b wheel with a 40mm tire is about the same as a 700c wheel with a 25mm tire. Of course the precise tires you use, as well as rim width will affect the exact
measurement.

We have a Calfee Tetra, customized for gravel use. We use 700c tire with 28mm tires on the road and 650b wheels with 48mm tires off road. The bike is not noticeably lower with the 650b’s.

It is a bit low and prone to heel strikes in serious off roading, but that’s the result of the geometry choices we made for road handling, not the wheel set

merlinextraligh

Also, if you’re looking for things to upgrade, I would seriously consider hydraulic disc brakes. It may not matter if you’re riding it in Houston, but for us, we were not satisfied with cable disc brakes in the mountains on 2 difereent co-motion tandems.

Admittedly, a full switch to hydraulic likely means an entire new group set which would be pricey.

A middle road option, which we found better than cable, but not quite as good as full hydraulic was TRP hybrid hydraulic brakes. They are plug and play with existing cable brake brifters.

Paul J

On the belt drive, it is cleaner, smoother and it responds more instantly, the last is hard to explain but we feel the difference between our two bikes. Our Bushnell, which is set-up for touring used a chain.

TobyGadd

I thought that I'd have to upgrade my BB7 brakes for steep descents in Colorado, but I've actually never needed to do it. If I change my mind, I'll probably go with Paul Klampers--which also don't require a new groupset.