Sub 7.3 kg/6.4 kg 29'er project buildthread finished pic p 6

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Martin.F
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by Martin.F

2nd ride today. I was doing around 7-800w standing up straight on a very steep section and the chain just popped off the smallest ring up front. I hit the stem with my stem (you know...), and after some swearing and shouting - scaring the mooses, I put the chain back on and tried again. 1 turn of the crank and the chain dropped again. I got off the bike and gave the cranks a spin, I bent the chainring around 5-8mm.

There was no roots or rocks on the trail, the rings have no marks from being hit and I know for sure I haven't knocked them into anything. They just bent under pressure.

The rings was Hellore 26T alu, and I don't want these again. Very soft and fragile. I accept a small weight penalty to get better performance, does anybody have any suggestions for a replacement?

26 or 27T chainring
Black or titanium color
64 BCD

by Weenie


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devinci
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by devinci

sorry to hear about that, hope you are OK

krzysiekmz
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by krzysiekmz

Similar thing happened to me. Bent the chainring and the chain dropped between the crankset demaging one of the granny bolts and got stuck as well.

Installed 27t FRM ring and also have Specialties TA as backup. These look solid and quality.

Chris.
Orbea Oiz - xxxx
MSC Koncept Carbon Di2 - 6955g
Leichtkraft Team Carbon - 6868g.

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Martin.F
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by Martin.F

Devinci: Thanks, yes I'm ok :)

krzysiekmz: Thank you for the suggestion, will take a look at the FRM. Specialites TA is probably a safe shot?

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devinci
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by devinci

I have a 42 T specialitie TA 120/80 on my XX crank and its holding great and shifts good.

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devinci
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by devinci

So Martin how is it going? I saw you are selling the cranks and read a comment about parting your bike and buying a stock bike...?

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Martin.F
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by Martin.F

Yeah, I couldn't get the bb to work with this frame, so I've done some changes.

Changed to a smaller frame. I did a 3hr race on the bike and actually came to the conclusion that I want it 1 size smaller. 1 Mail and 2 days later it was at the lbs. 10 points to liggero :thumbup:

Put on Sram XX cranks: 156q, 170mm, 42-28

Shimano XTR pedals. The eggbeaters are better om mud and in-out clicks, but the wider and larger platform of the XTR are both more confidenceinspiring and short bursts are more secure and stable than EB. EB are lighter, but XTR makes me faster. And after all, it is about winning races.

So thats -572g-168g+741g+308g = 310g gain - 7g lighter frame. Might do titanium spindle for the xtrs to reduce the damage..

I've played with the thought of getting tubulars, but I don't know which... I'm also thinking about biolog an Archtek/cx-ray/am classic wheelset. Hmm...

Edit: devincii, did the TA rings save weight over XX rings?

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Mattias Hellöre
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by Mattias Hellöre

Martin.F: Hope you are OK , why didn´t I know about the failure of chainring?
Send me a mail and hopefully we can solve it.
Experimental Prototype

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devinci
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by devinci

Martin

It was lighter but not much. IIRC it saved 5-9g over the XX ring but the XX ring had quite some use on it.

Fyi I have odered a mtb quarq. Will get it soon and Hopefully i can post a few comments on it

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Martin.F
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by Martin.F

Hellore: I bought it from r2-bike, and they refunded my money no questions asked :)

Devinci: 5-9 grams is not that much. What type of Quarq? I'm very pleased with my road version!

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Mattias Hellöre
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by Mattias Hellöre

Martin.F: good it solved for you.
I´v sold around 1500 to 2000 rings until now, I think I know about 1-3% of them has failed due to design flaws or other causes.
So the track record is quite good.
Experimental Prototype

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Martin.F
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by Martin.F

Yup, it solved perfectly, no complaints :) That is a good track record indeed. Especially when they are in so light.

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devinci
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by devinci

Martin

I ordered the sram mtb version 28/42 gxp

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Martin.F
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by Martin.F

Ooh, that is a very nice choise!

by Weenie


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Mads Kock
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by Mads Kock

If you're looking for light durable chainrings for sram xx - check out my lastest post on my blog. It's about Tune 39T vs. Sram XX 42T chainrings. Saved me 40 grams :-)

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