Chinertown
Chinese Carbon MTB => 29er => Topic started by: surferjo on March 13, 2018, 02:27:43 PM
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Hello All.
Ive been lurking on this site for a bit now. After doing a good amount of reading I finally decided to pull the trigger on a Carbon 29er Hard tail.
I currently ride a 26" Merlin XLM Ti frame.
The frame I purchased says Bottom bracket BSA 73mm. Bottom Brackets have really changed a lot since I built up my Merlin.
My question is will this bottom bracket work with my frame?
https://www.ebay.com/itm/RaceFace-Cinch-Bottom-Bracket-BSA-68-73mm-BB-Shell-x-30mm-Spindle-/122737612273?_trksid=p2349526.m4383.l4275.c10
If not can you make a recommendation?
Thank in advance for the help.
Joey
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What crank will you be using? The BB you linked is for 30mm spindles. Shimano use 24mm spindles on their cranks, Race Face use 24mm and 30mm spindles, Rotor use 30mm spindles, SRAM has their GXP standard, etc.
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Wow, I haven't even looked at cranks yet, Im glad I posted here. Im trying to build this on a budget, ill start looking at cranks now.
Thank you
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I believe that the linked B.B. will only work with RaceFace Cinch cranks which use a 30mm spindle. Yes it will work with the frame as long as you get a RF Cinch crank. Pretty much all the new RF stuff is Cinch. That’s just their BB system name, sort of like how Sram used GXP.
What sort of crank budget are you looking at? Arm length?
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I believe that the linked B.B. will only work with RaceFace Cinch cranks which use a 30mm spindle.
In fact, Rotor use the same BB standard as RaceFace Cinch cranks but if he's on a budget, Rotor cranks are already out of the game since they cost a lot. :)
Shimano SLX cranks clearly are best bang for $ . They are as light as XT if you use an aftermarket chainring like the RaceFace narrow wide ring or something similar (many vendor at various prices). They use BSA bottom bracket and have a 24mm spindle. You can get a XT BB for 25$ CAD at CRC so it's cheap.
http://www.chainreactioncycles.com/ca/en/shimano-xt-mt800-bottom-bracket/rp-prod135826
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Yup, most of the weight differences between models is due to using steal chainrings on the cheaper ones. I’ve been a fan of GXP cranks lately. I wish Shimano did a spiderless design like Sram and RF. XT cranks can be had for cheap too.
SurferJo, let us know your budget and we can help spend your money. ;D
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maybe look on the used market? many sell their older XT cranks for whatever reason.
Or maybe even try out IXF cranks(aliexpress). Surely they are heavy and no fancy hollowtech technology, but i got them for 29€ BB(Shimano 24mm Standard BSA) included.
If you are on a extreme budget and weight isn't much of a concern, they might work for you. They got the older 104mm BCD for the outer and 64mm BCD inner, so you could either reuse you older chainrings or get motsugov aluminium alloy 7075 series narrow wide. cost me under 7€ per piece. i got myself 32t, 34t, 36t and 38t for every situation, also all together cost less than a name brand chainring. They are also available in oval(i use them on every bike i own) so if you want to try oval, without absolute-black, rotor or osymmetric chainrings, thats a possibility
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Awesome. So for $123 I can grab a BB, CR and Cranks. That is well within my budget.
In your opinions would this be comparable/compatible?
https://www.performancebike.com/shop/bike-parts-components/cranksets-chainrings-bottom-brackets/mountain-cranksets/race-face-ride-xc-32t-crankset-special-edition-50-3919
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You need 170mm crankarm ?
Recently I bought this crank from AliExpress: https://www.aliexpress.com/item/SNAIL-Bike-Bicycle-Suit-Sets-Crankset-crank-Chainwheel-30T-32T-34T-7075-CNC-Narrow-Wide-Chainring/32837261586.html?spm=a2g0s.9042311.0.0.hVhDWe
It's a really light crankset, 756gr total (BB, crank, chainring). 649gr for crank with chainring.
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I’ve seen that same setup on eBay. I assumed it wasn’t compatible with the 73mm BSA socket on the frame I purchased.
I think I need a 170 mm crank. I’m 5’9 with a 30.5 inseam. Most of the things I’ve read about crank length seem to be very subjective but I believe I fall into the shorter 170mm category over the longer 175mm.
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In your opinions would this be comparable/compatible?
All the parts will fit with your frame.
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I’ve seen that same setup on eBay. I assumed it wasn’t compatible with the 73mm BSA socket on the frame I purchased.
Yes, it's compatible. I put it on a frame with 68mm BSA BB. Had to place two spacers and I didn't install the tube between the two cups, because the BB is closed and it save a little bit of weight ;)
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Thank you all very much for your help. you have saved me countless hours of research.
Side question. where in this description can you tell that this crank/BB combo is compatible with a BSA threaded BB Socket? For some reason all these different BB's is very confusing to me.
Material: 7075 T6 CNC aluminum alloy
Size: 30T 32T 34T
Crank size:170MM
Offset: 1mm and 6mm
Weight: 760 grams (including the axis)
Color: Black Red Blue
Suitable for GXP XX1 X9 XO X01 crankset
Package Include: Crank x 1
Chainring x 1
Axle X 1
Crankset screws x 3
Crank Screw X 1
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The BB which in the package is a (Shimano) BSA BB. The axle of this crank is 24mm, which is the same as the shimano Hollowtec II. The chainring is a GXP (XX1 X9 whatever) type, which fits this crank, but also SRAM GXP cranks.
It wasn't also clear to me, so I asked the seller.
But if you look closer to the BB's on the AliExpress page, you can see it's BSA.
Please look at the attached image.
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Well i have to say this has been an extremely helpful thread.
I think Im going to pull the trigger on the AliExpress $85 light weight combo package.
its not that much cheaper than the Shimano setup i listed ($113 after coupon code) but it is lighter.
As long as you all think I wont have any issue going with the AliExpress over the more industry standard Shimano im going to go with it.
Thanks
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I’ve seen that same setup on eBay. I assumed it wasn’t compatible with the 73mm BSA socket on the frame I purchased.
I think I need a 170 mm crank. I’m 5’9 with a 30.5 inseam. Most of the things I’ve read about crank length seem to be very subjective but I believe I fall into the shorter 170mm category over the longer 175mm.
At 5'9", you can go either way and be fine, it's personal preference. My wife has 170's on her Tallboy and I run 175, I can't tell the difference between the two.
These will up your budget some but it's good to have options. Any of the Sram GXP cranks will work, and the ones I've linked, have a removable spider. So if you go this route, you will need to remove the spider and get a direct mount chainring of your choice. You will also need a BB and those run around $25.
Aluminum crank arms with removable spider, comes with 32t ring. https://www.competitivecyclist.com/truvativ-descendant-6k-eagle-gxp-crankset-boost?skidn=TRU001K-BK-S170MM32T&ti=UExQIENhdDpNb3VudGFpbiBCaWtlIENyYW5rc2V0czoxOjE6Y2NDYXQxMDAxNDU=
This one has hollow aluminum crank arms and is a bit lighter. You will need to remove the rings and/or the spider and get the ring of your choice. This should have a 104bcd and you have the option of running a standard chainring on the existing spider.
https://www.competitivecyclist.com/truvativ-descendant-6k-eagle-gxp-crankset-boost?skidn=TRU001K-BK-S170MM32T&ti=UExQIENhdDpNb3VudGFpbiBCaWtlIENyYW5rc2V0czoxOjE6Y2NDYXQxMDAxNDU=
This one is carbon and since it's a 2x spider, you really can't use it on a 1x system and will need a direct mount ring. But it's the lightest of the bunch and relatively cheap.
https://smile.amazon.com/gp/product/B003UW490M/ref=ox_sc_act_title_2?smid=ATVPDKIKX0DER&psc=1
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I know this is a little off topic, but has anyone tried carbon cranks from Aliexpress? Most cost as much as regular XT cranks and are specified to be ~300g lighter. Most people here seem to buy cranks from name brands ... is this because they're more trustworthy or were there major bad experiences with Aliexpress cranks?
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This one is carbon and since it's a 2x spider, you really can't use it on a 1x system and will need a direct mount ring. But it's the lightest of the bunch and relatively cheap.
https://smile.amazon.com/gp/product/B003UW490M/ref=ox_sc_act_title_2?smid=ATVPDKIKX0DER&psc=1
Just a heads up, the SRAM X0 comes with a detachable spider and you can buy a 1x spider for the same chankset all over Ebay:
https://www.ebay.com/itm/Bicycle-BCD104-Spider-Adapter-1-x-System-for-Sram-GXP-XX1-X0-X9-Crank-Convert/272687253945?hash=item3f7d6d49b9:g:qdMAAOSwYvFZJ2Fp
I do have this on one of my bikes and it is a fantastic crankset and a bit underrated.
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I know this is a little off topic, but has anyone tried carbon cranks from Aliexpress? Most cost as much as regular XT cranks and are specified to be ~300g lighter. Most people here seem to buy cranks from name brands ... is this because they're more trustworthy or were there major bad experiences with Aliexpress cranks?
I think it was on MTBR forum, a weight weenie guy tried the chinese carbon crank with 104 BCD spider and broke it in no time where the bolts are holding the chainring. I would definitly go with a direct mount chainring option if I was trying those cranksets.
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Just took a look. For the price the weight is tempting. I don't see any direct mount cranks.
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The 3 Sram or Truvativ cranks that I posted links to all have a detachable spider. If it's a 3x crank, then it will use a 104bcd bolt pattern and you can put any 104bcd in the middle ring position. Or you can remove the spider and rings as a unit and put a direct mount chainring on. Absolute black, WolfTooth, RaceFace, Blackspire and many others make compatible direct mount rings. I have Absolute Black ovals and BlackSpire round rings and all have been great. The Blackspire is probably the cheapest option.
http://www.chainreactioncycles.com/us/en/blackspire-snaggletooth-narrow-wide-chainring-sram/rp-prod144516
There is about a 100 gram difference between the carbon X0 crank arms and the hollow aluminum X9 cranks arms. That's just the arms, no spider or rings attached. I'm not sure what the weight difference is between the hollow aluminum and the solid ones are.