ahultin

I have a Cannondale rt1 built from frame up a couple years ago. It was built di2 with xtr triple components. I have put about 2600 miles on it and just replaced the chain again (replacing at @1250 mile intervals)as it was measuring 1/16 wear. With the new chain I am getting skipping of the chain rings when under load which tells me I need to replace them. I have middleburn rs8 xtype cranks wjth middleburn hard coat rings and honestly though they would have lasted longer. Triples seem to be going extinct and I cannot seem to locate replacement rings other than ordering them from middleburn again.
2 questions:
1. Is there an alternative set of triple rings anyone recommends? Spider is currently 104/64 48/36/26
2. 1 of my stokers has a calfee with di2 double and it shifts so much nicer. I may be open to ordering a new spider and swapping to 2x if I can do it with the 3x xtr front derailleur

Kevinti

Did you look at ebay ?

ahultin

yup, first place I checked, lots of used options but i dont think thats a worthwhile attempt

Leisesturm

1200mi out of a chain? There is a problem somewhere. Skipping does not always mean the chain is worn! There is another problem somewhere in the o.p. drivetrain and they may want to track it down. I know just about nothing about electronic shifting which is kind of unusual because I try to make a point of knowing at least a bit of everything. Still, at the end of the day, the shifting is an important but small part of it all. The chainwheel has to move the chain over the rear cogs and down the road you go. Unless E-assisted, chainwheels do not (normally) wear. Most of the vintage bikes I find still have their original chainwheels. I don't know, if I had a friend and they were getting more joy than me from their drivetrain I might take my tandem to the same shop that worked on theirs?

ahultin

I found a couple places selling a set of blackspire super pro rings. Anyone have experience with these? They are 44/32/22 which is closer to xtr m9050 spec than the 48t I currently have but I'll lose too end which is OK

ahultin

I try and replace the 11 speed chains when the 12" measurement is at 12 1/16 which represents 5% "stretch". Team weight was often over 500lbs which does a number on all bike components, chainrings included. I have in my past chewed thru components thatost find indestructible.
team weight is significantly lower now but the damage has been done.

Ross200

TA and Stronglight both make very durable chainrings in that combination.

How is your chainline? Middleburn/BETX have some choices for spider offset and BB length/spacers to adjust chainline. The teams I've spoken to about their DI 11 Spd triples have ben very pleased.

oldacura

1250 miles on a chain sounds crazy low to me as well but 1/16" / 12" is definitely a lot of stretch (wear) as well. However, our team weight is more like 300#.

I have used Blackspire chainrings on my mountain bike and like them pretty well. Even if the rings have a hard anodized coating (aluminum oxide), the coating will wear through fairly quickly and you are left with a steel chain against aluminum.

Though I have never purchased a bike from them I have gotten great advice on Di2 doubles & triples from House of Tandems in Texas. I forget the owner's name but he was very helpful with free advice:

https://www.houseoftandems.com/

Good luck

longpete

11 speed chains on a tandem certainly with di2 last less long but 1250 is very short for onroad. Try using 3 chains and change every 300 km or wet ride. When you live in a dry climate wax your chain instead of oiling.
I use CNLG500 linkglide chains.Unbeatable price quality. Wipperman connex chains cost more than double but don't last longer. Only advantage of wipperman : better resistance against rust.

Kevinti

Are you saying to rotate between three chainsets every 300km and after a wet ride?

longpete

Yes

oldacura

What would rotating between 3 chains accomplish?

Freerojo

I would check and make sure rear wheel is centered correctly and much force applied to quick release. There is theoretically twice as much torque on the drive forcing rear wheel a tad off center to the left. Of course the cassette is now off center.

masi61

I bought a triple set of KCNC "cobweb" CNC 7075 chainrings in the 104/64 BCD size. I plan to use them on a Cannondale Silk Tour bike that I am restoring. They would fit your tandem cranks I think. No idea if they would be durable though. I would be more inclined to check and see if Praxisworks makes some cold forged rings in the BCD you need.

ahultin

sadly, praxis no longer makes any triple rings. Ill look up kcnc and am waiting to hear back from blackspire which of theirs would be appropriate

ahultin

chainline is currently 55mm for 145oln hub

ahultin

And for today's entry in the "well we've never seen that before" category. I beleive the issue may have been located :

longpete

Longer life chainwheels and cassette especiallly with 11 and 12 speed where a chain worn around 0.5
causes a lot of wear. Combined wit wax i tripled the life of my driving components. Onroad+dry even lasts longer.

masi61

can you explain further? Is it excessive wear on one of the chainrings? Or something to do with the axle? I can’t tell.

ahultin

Spider lock ring is cracked which under lateral force allows the spider to rock enough to throw or skip the chain

Alcanbrad

You may have found the root cause in the lock ring. I did want to add a comment anyway should the lock ring not cure your problem. I upgraded from an old ultegra mechanical triple to etap red double and we had a big issue with the chain skipping from to start (I.e the entire drive train was new). I was convinced that our problem was ghost shifting when under extreme load as it only occurred in a couple of gear combinations.

I was not able to solve it until I put a GoPro on the rear cluster and discovered it was actually skipping on the front ring. You can read all about it in this thread Pretty much given up on ETAP Red, now considering 10speed Hydraulic.

It turned out the the small chain ring was the cause and replacing with a better quality chainring immediately cured th problem. The problem chainring was special made for this conversion. I never considered that a brand new chainring (with brand new chains) would be the cause. If the chainrings you have are low volume and from a boutique manufacturer, they may not be the best.

My comment: as we too are a heavy team, don’t rule out the brand of chainrings as a possible cause of unwanted skipping,

Monoborracho

Rene Herse Tandem Triple Crank – Rene Herse Cycles


Peter White Cycles look around here under Products / Drive Train