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Do i need to use tandem specific cranks?
Can i just use two single speed cranks for the non drive side an then a normal double / triple on the drive side? so, put a normal crankset on the wrong way round on the front.
obviously, the gearing on non-drive would need to match, though, actually it probably wouldn't need to except maybe for steep cornering.
Yes but you would need to heili coil the cranks that where on the wrong side.
Pedal threads. So, no, not unless you remove the old threads and helicoil new ones in as suggested above.
Or get a Rohloff tandem and then you can use normal cranks 🙂
Yes you can, but as above they would need to be helicoiled. Doesn’t cost a huge amount to do. You also need either ISIS, HT1 or square taper cranks.
The gearing on non-drive side DOES have to match, it’s super awkward otherwise.
You also need either ISIS, HT1 or square taper cranks.
Surely HT2 would also work?
Couldn't you have a timing chain on the right, on say the smallest chairing, and then have the rear chainset set-up double on the middle and big ring?
Not necessarily, if you run 1x or a rohloff like is then you can run a nornal cranks with a timing chain to either the inner or to an outer ring for the chainline, We run 2 pairs of aeffect cranks, direct mount front and then spider on the rear for the two chain rings needed there.
Couldn’t you have a timing chain on the right, on say the smallest chairing, and then have the rear chainset set-up double on the middle and big ring?
That would work (subject to having to make chainline compromises; you'd really want a 3-piece crank to adjust this), as would 1x. Though (depending on what you're using it for and how powerful your stoker is) you generally want a huge gear range on a tandem and losing the granny ring will hurt. I guess now that we have 50t cassettes it may be more viable.
Bez - HT2 wouldn't work for the stoker left hand crank 😉
HT2 wouldn’t work for the stoker left hand crank
Ah yes 🙂
Helicoiling would require drilling out the (wrong direction) thread..would the resulting hole work for tapping the coil in?
Also confused about why HT2 woulnd't work for stoker NDS bit I hope it will come to me...
Also confused about why HT2 woulnd’t work for stoker NDS bit
Because it'll have a spindle attached to it.
The stoker cranks traditionally have chainings on both sides. HTII the crank and spider are attached to the axle, so you can not mount two on the same axle like you could with the other systems.
<div class="bbp-reply-author">Bez
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<div class="bbp-reply-content">Also confused about why HT2 woulnd’t work for stoker NDS bit
Because it’ll have a spindle attached to it.
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But you were talking about having both chains on the DS...
But you were talking about having both chains on the DS…
That came later. The comment this harks back to was about helicoiling cranks to run a left hand timing chain.
hmm, sounds like triple might be the best solution, if i intend to use lying around' bits
Edit: Why does Rohloff make a difference?
Rohloff needs only 1 chainring and no derailleurs/chain movement. (I guess Alfine etc not up to the torque)
Ta Bez, thought I was going bonkers
I couldn't afford kiddy cranks for my Tandem, so used standard triples 175mm for the pilot and 155mm for the stoker on the back.
42T outer ring only on the pilots chainset
standard 22T 32T 42T on the pilot chainset.
Timing chain runs on the 42T big rings and the rear derraileur limit screws are adjusted so it can only select the 22T and 32T rings.
It works really well, we lose top end speed but the kids don't like going any faster than the 32-11 top gear anyway.
Why didn't I think of running the timing chain on the big ring? Duh! Yeah, do that if you want to get up hills. Run it on the inner ring if you're doing a time trial 😉
Beware trying to do single sided drive on a tandem. I tried on my rohloff tandem. When using adjacent chainrings for timing and final drive there was not enough clearance ( 9 sp chainrings and chains). the two chains clashed. Use the granny for the timing chain it will wear out very quickly. If you can get it to work its the best solution but actually getting it to work is very difficult I found.
Runs fine on my Rohloff tandem. 8sp chains, timing chain on the middle ring and drive chain on the outer.
As an alternative to helicoiling, you can switch the pedal axles and use threadlock. At your own risk.
Its interesting Bez - when I tried that they clashed the two chains touched
when I tried that they clashed the two chains touched
Does it not depends on the size of the outer ring? If it is large enough you can probably avoid the clash, if they are similar sizes you are likely to have problems
not size dependent as they clashed because not enough room between them horizontally. Why my setup was like this but others are not I cannot fathom
SJS / Thorn used to sell a tandem with rh timing chain (using XT cranks I think).
Allegedly the rear bb lasts longer as the rh front / rear chain tensions partially cancel each other out. I must admit our old tandem used to eat rear bbs (normal lh timing chain)
@tjagain It just so happened that I changed the ratio on the tandem at the weekend and I noticed I'd previously fitted washers (~1mm) between the spider and the timing chainring. It's 13 years since I fitted them and that's my excuse for forgetting they were there 🙂
Ta Bez - that would be why then. I couldn't figure out why I couldn't do it but others could.