Dolan Pre Cursa chainstays issue

Hi

I'm working on my first build and have a Dolan Pre Cursa frame and Miche Primato Advanced Chainset with a Mack track hub (chainline 42mm). I know a post has just gone up with a transmissions database but it seems there's a specific issue with chainstay rub on the Pre Cursa when using the recommended 107mm BB. Anyone had this issue and does anyone know if using a 110mm BB would be possible?

Thanks.

1) Are you using the Miche 107mm bb or another brand?

2) If Miche, is it rubbing on both sides?

3) If not Miche, what type of taper?

We have Dolan PC + Miche Primato Advanced + random assortment of bb (but none on miche bb) on the hire bikes at work. Some have a thicker lip on driveside cup and so (Ithink) don't screw in as far, these tend to be ok but the ones with thinner lip need a spacer. Could also be down to manufacturing inconsistency in cheaper bb, they are Acor etc.

Just got my pre cursa frameset a week ago. I'm using Miche Primato Advanced chainset. I got installed a 107mm bb and the right crankset was hitting the chainstay when i was pedalling hard. I had to fit a longer bb. Now im using a 113mm bb. I didn't try it with 110mm, it might work, i dont know. I still have a very small clearance between the crank and the chainstay but at least it doesnt hit the frame. I was a bit worried because of the chainline with the 113mm bb, but its okay. The 44mm chainline on the mavic ellipse hub compensates the wider bb a bit.

This article mentions the same problem. He fitted a 111mm bb, and it was okay for him.

http://www.glasgowwheelers.com/tommysTrackRecommendations.php

" I have recently fitted a Miche chain set to a Dolan pre-cursa frame and found that with the correct length ISO taper bottom bracket of 107mm, the right hand crank was hitting the chain stay. I had to fit a 111mm long ISO taper bracket to correct this, even so the crank was close to the chain stay. I measured the distance between the chain stays at this point and found it to be 100mm, which compares to 95mm on my own frame at the same point. With the longer bracket the chain alignment was however good so this was not a major problem."

Dolan should really solve this problem, maybe redeisgn the chainstay area a little bit, so the one could use a bigger variety of cranks on this pretty nice frame.

Just saw a 110 BB for sale here:

http://www.lfgss.com/thread102525.html

Thought it might help.

Ben, he needs iso though!

Is this only a problem with Miche? Quite a lot of people I see are running the Stronglight Track 2000 with the Stronglight JP400 107mm BB on Pre Cursas and I had an issue with this set on my bike previously.

I plan on getting a Pre Cursa for track use only and worry that my Hatta R9400 and Dura Ace 7600s might have a similar problem (they have the same problem that the Stronglight set had on the same frame).

@mechanical_vandal

I haven't got the BB yet as I'm not sure on the length, do you know which BBs don't have the chainline issue on your rental bikes?

And yes, I need ISO and the Pre Cursa is English threaded.

Just got my pre cursa frameset a week ago. I'm using Miche Primato Advanced chainset. I got installed a 107mm bb and the right crankset was hitting the chainstay when i was pedalling hard. I had to fit a longer bb. Now im using a 113mm bb. I didn't try it with 110mm, it might work, i dont know. I still have a very small clearance between the crank and the chainstay but at least it doesnt hit the frame. I was a bit worried because of the chainline with the 113mm bb, but its okay. The 44mm chainline on the mavic ellipse hub compensates the wider bb a bit.

This article mentions the same problem. He fitted a 111mm bb, and it was okay for him.

http://www.glasgowwheelers.com/tommysTrackRecommendations.php

" I have recently fitted a Miche chain set to a Dolan pre-cursa frame and found that with the correct length ISO taper bottom bracket of 107mm, the right hand crank was hitting the chain stay. I had to fit a 111mm long ISO taper bracket to correct this, even so the crank was close to the chain stay. I measured the distance between the chain stays at this point and found it to be 100mm, which compares to 95mm on my own frame at the same point. With the longer bracket the chain alignment was however good so this was not a major problem."

Dolan should really solve this problem, maybe redeisgn the chainstay area a little bit, so the one could use a bigger variety of cranks on this pretty nice frame.

I'm afraid I couldn't really recommend listening too closely to much that Mr Banks has to say.

Is this only a problem with Miche? Quite a lot of people I see are running the Stronglight Track 2000 with the Stronglight JP400 107mm BB on Pre Cursas and I had an issue with this set on my bike previously.

I plan on getting a Pre Cursa for track use only and worry that my Hatta R9400 and Dura Ace 7600s might have a similar problem (they have the same problem that the Stronglight set had on the same frame).

Think we are talking about 2 different problems here (or maybe just I am), Stronglights rub at the spider, our Pre Cursa/Miche Primato Advance/Random bb combo sometimes rubs at the end of the crank arm, behind the pedal boss.

@mechanical_vandal

I haven't got the BB yet as I'm not sure on the length, do you know which BBs don't have the chainline issue on your rental bikes?

And yes, I need ISO and the Pre Cursa is English threaded.

No.

The bikes were prebuilt so I don't know what bb went into each and have only had a few out to spacer them and even then, recording the type of bb wasn't in my mind at the time.

I'm just about to put a bb and cranks into a 58cm frame though and think I have two different bbs to chose from so will report in a mo with my findings.

Ok, one bb was 103mm so it was miles off.

The other was a 107.5mm Acor unit. No idea what type of taper that has, I'll leave that research to you.

It gives this gap at the chainstay,

and this chainline with a Novatech hub,

In that top pic you'll see the fairly thick lip the bb has, the ones that need spacers I think have a thinner lip, whether that indicates a different marque or model of bb or just a different production batch I'm not sure.

Wow, thanks so much for that, great to see pics, hope I can get the same result.

I just got a reply from Jamie at Dolan who said they've used 110mm BBs with the Miche Primato Advanced and a 42mm chainline and had no problems.

If I can find a dirt cheap 107mm BB I might see what result it gives and go from there.

Once again, thank you for all your input.

I messed up my bb shell and need to use the threadless bb's only find then in a 110mm though and my miche primato cranks are 107mm.... Problems? Think primato cranks use to be 110mm bb anyway didn't they.

Paying £50 or so for a sleeve job beats using a threadless any day of the week.

Are they that shit lol

That and a sleeve repair leaves you with a frame that's (so far as the bb is concerned) good as new.

Just on my way now to get the bb shell retreaded :-)

i have this sam eissue and this is why i signed up to this forum.

I have recently purchased a miche primato advanced chain set. The drive side crank extends further onto the bb spindle than the left side crank does and it hits the chainstay once tightened. The left crank however actually has adequate chainstay clearance and so I am curious if the cranks were intended to be non symmetrical or if the drive side should not extend so far onto the spindle and is faulty or damaged. I use a miche 107 bb for a 42mm chainline and i installed the bb correctly that the cups extend into the frame equally, also my frame is properly aligned.

the crank/chainstay clearance should be equal on both sides for a fixed gear, symmetry and balance are important on the track and so is a narrow q factor. are these cranks faulty or intended to extend on the cranks differently it seems a number of people have had the exact same issue. but non have been so concise when explaining the issue only on how to bodge it up with an incorrect chainline. any chain line which is out is a bad chainline...

the driveside crank seems as if it has been repeatedly reinstalled and overtightened too many times whereas the left side crank has a perfect amount of clearance from the chainstay and extends onto the spindle just the right amount as a brand new crank would.

miche

There's your explanation.

Sounds like a driveside bb spacer would fix the issue if it's a flanged driveside cup, if it's the adjustable Miche bb, just float itover a bit.

this particular bottom bracket does not have flanges on either side and can be adjusted but it doesn't mean that it should be. adjusting the bottom bracket will expose the threads on either the bottom bracket cup or the frame, also it would need a good 3mm to be symmetrical and give safe clearance.

i think i could find the answer myself by measuring the chainline on the front but i a cant be quite accurate with only a ruler. i figure that if the chainline measures 42mm on the front then the intended design was to be non symmetrical, and if so by conclusion the miche cranks are as bad as cycling through dog turd and they dont live up to the great rep everyone gives them.

more interestingness. when installed the driveside crank has no clearance from the chainstay but when moved to the left side and installed there is clearance! i figured i could ride a left hand drive but what this actually showed was that the frame is slightly out of alignment by 1-2mm and when it comes to a narrow q factor this is noticeable.

a quick google found a number of people with this issue so i thought i would share my review and analysis from first hand experience.

the miche cranks...dont live up to the great rep everyone gives them.

You must be new here.

Does the bb axle protrude symmetrically from the shell? Ie there isn't more axle on the left than there is on the right? I think it's Campy that make the asymmetrical bottom brackets but you never know.

Our Pre Cursas are running Miche cranks but not miche bottom brackets (coz they're shitter than the cranks). We've had to put drive side spacers on probably 90% of them to stop the crank arm hitting. Chain line seems fine so dunno if it was mince before the spacer or whether you can just get away with a few mm without issue.

If I was you, I'd ditch the miche bb and replace it with a non adjustable flanges one and go for either a slightly longer axle or a drive side spacer.

Oh another thought, it's rubbing at the end yeah?

Could the drive side crank be bent? We've been seeing them go banana-like from even minor crashes.

the bb itself is symmetrical. simply, the drive side crank extends further onto the spindle than the left side. which ever side of the bb spindle the crank is placed on.

i don't want to know how to bodge it up or if the chainline 'seems' ok. any chainline which is out is a bad chain line. the problems with a bad chainline are increased wear, loss of power and lack of safety. the safety issue being that when a chain is not tight there is an increased risk of the chain falling off and this risk is greater when the chainline is out. now a few millimetres is not easy to spot with the eye, just measure it with a vernier caliper, every bike shop should have them...

if "90%" of the miche cranks hit the chainstay on a pre cursa frame im wondering why the other 10% does not. do these anomalies arise from the frame or the cranks? or a combination of both being badly designed.

my conclusion is that the cranks were intended this way, for the drive side to extend further on. i believe this was intended to maintain a 42mm chainline. a compromise as to maintain the aesthetic look of the cranks which are relatively straight.

just to conclude this. the pedals should extend equally from the frame.
also for intended safety.. if a chain falls off a bike this means something is wrong, it could just mean you need to tighten it. but when it comes to a fixed gear where your chain is your means of braking its imperative that this is set up properly because if your chainline is out the chance of the chain falling off is increased and more likely to happen when you brake.

my original question was if the drive side crank was intended to extend onto the bb spindle further than the left side crank or if this was a fault or damaged.

evidently all other miche primato advanced chain sets do the same thing so there is no fault or damage. i guess there is nothing wrong with the chain set it just doesn't fit onto the pre cursa without an unsafe bodged up system.

i would like to have tried one more experiment, another 107 bb but i'm left unsure if it is iso or jis. miche apparently use iso like campagnolo yet miche list the chainset as using a jis here http://www.miche.it/en/catalogo/catalogo-miche/guarniture/guarnitura-primato-advanced-pista

...worse than cleaning dog turd off your tyre tread.

Do you know if the dolan pre cursa requires a 68 or 73 sized shell?
Thanks