TCR build

Discuss light weight issues concerning road bikes & parts.
Gluestick
Posts: 7
Joined: Mon Mar 17, 2014 1:47 am

by Gluestick

I am pretty close to pulling the trigger on some new wheels for my TCR disc. I am planning to go with Lightbicycle rims and am intending to run 25c Conti GP 5000's for rubber. I am a bit stuck and am hoping those in the know can offer some input. I am between the AR56 (23 internal, 30 external) and the R55 (17.9 internal, 25 external). I have read enought to know that 28c is pretty much a no-go on the TCR (in the rear at least) and am curious if: 1) the AR56 with the 23i would stretch out a 25c Conti so that it would not fit and 2) would I pay an aero penalty for the increased comfort with the AR56 as it has a fat 30mm external width.

Thanks

Glue

Hexsense
Posts: 1219
Joined: Wed Dec 30, 2015 12:41 am

by Hexsense

1.) 25c GP5000 on AR56 will fit. GP5000 25c is only a little bit bigger than GP4000sII 23c. I think even 28c will fit but with low clearance.
2.) Actually the opposite way, you pay aero penalty if you use R55 and any tire wider than 23.8mm. So with rim as narrow as R55, you may want 21c-22c to not break 105% "guideline".
AR56 will be faster than R55 in term of aero for normal size 23c-28c tires because the rim width is better conform with tire width.

by Weenie


LiquidCooled
Posts: 189
Joined: Mon Oct 02, 2017 5:46 am

by LiquidCooled

I have a TCR Disc and LB AR56 wheels. I run Vittoria Corsa G+ 28mm tires, which measure about 30.5mm on those rims. I have no issues with clearance with the frame (min 3.5mm clearance everywhere). I’m loving this tire/wheel combo. I might change the front tire to a 25mm to get under the 105% rule. Or I might not. I’m skeptical that it will make a lot of difference—aero-wise—for me.
Last edited by LiquidCooled on Wed Jan 08, 2020 12:16 am, edited 2 times in total.
2017 Giant TCR Advanced Pro 0 Disc
2003 Cannondale R1000 (CAAD7)

bbee
Posts: 5
Joined: Thu Feb 09, 2017 3:36 pm

by bbee

I have a TCR Disc with Enve 3.4 wheels, which are 21mm internal, and GP5000 28mm tires. I haven't had any clearance issues front or rear.

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Gluestick
Posts: 7
Joined: Mon Mar 17, 2014 1:47 am

by Gluestick

Thank you all for the replies. Sounds like the AR56 is the way to go. Now I am wondering if the 28c 5000s will fit. I have read here and there about clearance issues not with the seat stays but with the seat tube. Anyone have experience with the 28c 5000s on a TCR? I am guessing the wider internal diameter rim will help flatten it wider rather than poof it out towards the seatstay.

alcatraz
Posts: 3102
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Choose tire and rim together. Ignore the tire label markings.

If you want a 25mm setup you probably need to go with ~25mm wide rims at the brake track and GP5000 23C tires. If you want a ~27-28mm setup you go with those rims and GP5000 25C tires. If you want a ~30-31mm setup you go with those rims and GP5000 28C tires.

Don't put 25C tires on 25mm rims or you'll pay a penalty.

Heavier riders or crappier roads need wider setups. Decide what you need in real measured mm.

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itsacarr
Posts: 847
Joined: Fri Nov 14, 2008 4:55 am
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by itsacarr

This has been said a few times on here (search..) but FYI ENVE AR 4.5s with 30mm tires will fit on a TCR disc. That is the absolute limit though 😬

cjm
Posts: 28
Joined: Mon Jan 14, 2019 12:56 pm

by cjm

The R55 are 28.02mm at the widest section if that helps with the 105% issue...

Gluestick
Posts: 7
Joined: Mon Mar 17, 2014 1:47 am

by Gluestick

So going with the AR56, what is the faster conti 5000 choice- 25 or 28c (I am presuming the 28c 5000s will fit the frame)? I understand the 105% rule, I am just not clear on how much these wider wheels will stretch out the 5000s and what that tire/wheel interface would look like. For user reference, this is my "fast" bike. I am nothing special but can hold my own on most local "A" rides. Road surfaces are typical New England- not especially smooth with spotty chip seal and normal weather induced imperfections.

Hexsense
Posts: 1219
Joined: Wed Dec 30, 2015 12:41 am

by Hexsense

Gluestick wrote:
Mon Jan 13, 2020 4:26 am
So going with the AR56, what is the faster conti 5000 choice- 25 or 28c
Both.
25c front for 105% rule.
28c rear for low rolling resistance and comfort where it support most of your weight.

Then you can use same pressure front and rear instead of adjusting for 40%/60% front/rear weight distribution.

Gluestick
Posts: 7
Joined: Mon Mar 17, 2014 1:47 am

by Gluestick

Thanks Hexsense, that is a great idea!

LiquidCooled
Posts: 189
Joined: Mon Oct 02, 2017 5:46 am

by LiquidCooled

Even if you run 25mm front and 28mm rear, you should still experiment with tire pressures. I run those sizes on my stock wheels (SLR1s) and I still prefer 5 psi less in the front. For reference, with 28mm all around (like on my AR56s), I run 10 psi less in the front.
2017 Giant TCR Advanced Pro 0 Disc
2003 Cannondale R1000 (CAAD7)

DCcyclist
Posts: 98
Joined: Tue Aug 22, 2017 2:09 am

by DCcyclist

I have stock SLR1s on my TCR Pro 0 and been wondering if I should upgrade and never been able to justify the cost. Are ENVE, Zipp or other expensive brands really worth it?

As a separate note, I run Spesh Turbo Cotton Hell of the North tires and there's plenty of room between either the chainstay or the seat tube. I always get the same size for front & back but next time I will go one size smaller for the front just for fun.

I also agree with Liquidcool's comment on experimenting. I think the sweetspot for my setup is 80 in the from 85 in the back. It was so smooth and fast on yesterday's ride. I wish there was a cheap way to track the tire pressure vs performance for each ride and analyze the data. Or maybe I should just ask my wife to get me a Quarq TyreWiz for xmas next year :))
2019 Giant TCR Advanced Pro 0 Disc

LiquidCooled
Posts: 189
Joined: Mon Oct 02, 2017 5:46 am

by LiquidCooled

DCcyclist wrote:I have stock SLR1s on my TCR Pro 0 and been wondering if I should upgrade and never been able to justify the cost. Are ENVE, Zipp or other expensive brands really worth it?
My LightBicycle AR56s are lighter, stiffer, wider, and more aero (56 mm deep vs 32mm) than my stock SLR1s. While they are only marginally more comfortable, the aero difference is surprising. Once you exceed 30-35 kph, it’s as if you have an extra gear. They were definitely worth the sub-1K $$. There’s no way I would spend $3K on Enves, etc., though.
2017 Giant TCR Advanced Pro 0 Disc
2003 Cannondale R1000 (CAAD7)

shotgun
Posts: 319
Joined: Tue Dec 30, 2008 3:38 pm
Location: Philippines

by shotgun

DCcyclist wrote:
Mon Jan 13, 2020 10:24 pm
I have stock SLR1s on my TCR Pro 0 and been wondering if I should upgrade and never been able to justify the cost. Are ENVE, Zipp or other expensive brands really worth it?

I guess you'll need to determin the "worth" first. Weight difference with the more expensive ones can by just 50-150g, depending on rim depth and width. Hubs of the Giants should be based on DT Swiss, so they're pretty robust. Assuming you'll select similar depths, aero performance will be fairly similar.
2018 Giant TCR Advance SL0 Disc
2017 Festka Scalatore
1989 Battaglin Roche
1985 Alan Carbonio

by Weenie


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