SRAM RED GCP Cranks & Chain Ring WEight

Discuss light weight issues concerning road bikes & parts.
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RezaTrek2200
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Joined: Mon Nov 28, 2016 5:52 am

by RezaTrek2200

I have searched long and hard and have not found the following weight Matrix. Can anyone help me please with the following.

What are the weights for the following configuration (excluding the Bottom Bracket):

SRAM RED GXP:

172.5mm 53/39, 52/36, 50/34
175 mm 53/39, 52/36, 50/34


I have a 175mm 53/39, on a 56" Frame, I am 5'10". Thinking of switching to a 172.5mm 50/34. Would love to know what the weight difference is between the two !!!


Many thanks for all your help !

by Weenie


JoeFlan
Posts: 103
Joined: Tue Jan 28, 2014 8:06 am

by JoeFlan

2013 Sram Red Exogram Crankset GXP 172.5 50-34t Chainrings: 569g
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Current Steed
Supersix Evo 6.25kg
Giant TCR SLR 6.8kg
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RezaTrek2200
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Joined: Mon Nov 28, 2016 5:52 am

by RezaTrek2200

Thanks so much. Hopefully others sill chime in for the other setups

cnyn
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Joined: Mon Dec 29, 2014 12:33 pm

by cnyn

SRAM Red eTap Groupset, 172,5mm, GXP, 50/34

Image

RezaTrek2200
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Joined: Mon Nov 28, 2016 5:52 am

by RezaTrek2200

Are the etap cranks different? I thought SRAM red crabks were all the same

cnyn
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Joined: Mon Dec 29, 2014 12:33 pm

by cnyn

No. I bought the crank with eTap Groupset but it's similar to the Red cranks. Claimed weight 609 g.

RezaTrek2200
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by RezaTrek2200

I wish SRAM would just post the weights for different configurations.

qorwlch
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Joined: Sun Oct 20, 2013 3:03 pm

by qorwlch

bb30 172.5 50/34t

red22 crank set weight is 517g
:x

RezaTrek2200
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Joined: Mon Nov 28, 2016 5:52 am

by RezaTrek2200

Wow BB30 is that much lighter, almost 50g

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prendrefeu
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by prendrefeu

Big diameter spindle = less material in the spindle necessary = lighter.
Exp001 || Other projects in the works.

Hexsense
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by Hexsense

prendrefeu wrote:Big diameter spindle = less material in the spindle necessary = lighter.

Not just less, Sram use Steel in GXP but Aluminum in BB30 's spindle.
They don't think Aluminum in 24mm spindle is stiff enough so they only use it on 30mm version. (Shimano dura-ace 's spindle is also steel)

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prendrefeu
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by prendrefeu

That is correct.
Exp001 || Other projects in the works.

by Weenie


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mythical
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by mythical

Steel is still heavier than aluminum in terms of mass. However, since the amount of material would weigh about the same to achieve an equal stiffness, due to the modulus of steel and aluminum. Cost probably has more to do with it, and compatibility with the other groupsets. The same axle, perhaps made with slightly different grade of the same material, can be used on many cranksets throughout the range of groupset levels and the production process would remain about the same. Sram has been using steel axles since the inception of GXP. It's perfectly possible to make aluminum axles for GXP cranksets, but this would cost a significant alteration in the product line, something not economically worthwhile on the scale of business Sram is operating. Mostly likely Sram persists to milk the patent of the GXP crankset technology.

My business strategy would be to develop a whole new line of cranksets with the BB386EVO in mind (Ø30mm axle with 86mm outside-to-outside bearing spacing) and create an all-out better crankset that is slightly lighter and stiffer and with a direct compatibility with more the frames on the market, and forego that pesky BB90 standard that e.g. Trek uses that IMO needs to get dropped anyway. I would also develop a new and integrated (hollow?) chainring standard similar to Shimano.
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