Scott CR1 Team Issue - Changing to Compact Crank ?

Back by popular demand, the general all-things Road forum!

Moderator: robbosmans

Post Reply
KarlC
Posts: 1028
Joined: Fri Dec 05, 2014 2:08 am
Location: De Portola Wine Trail Temecula CA

by KarlC

Hello all I'm looking for some input .....

I would like to go with a Compact Crank on my CR1 but I'm very new to this sport and don't know how to do it. Can I get some input on some good 2nd hand light weight crank sets you would recommend.

Right now I have the Dura Ace 7800 group set, the crank arms are 175, I think they are a bit long for me so that plays into it also.

On the CR1, the derailleur clamp is mounted with rivets to the frame and cannot be moved. There is a slot in the bracket to allow for a small amount of up/down adjustment. Will this be an issue ?

Do I need to change the bottom bracket at the same time? How do I tell what size it is ?

Goals are
- Compact Crank
- 172 arms
- Reduce weight if I can
- Overall still looks good with my bike

Thanks for your input, photos of my bike below

Image

Image
C64 My Sixty 4 SR EPS 12

User avatar
Gazelleer
Posts: 735
Joined: Mon Nov 01, 2004 3:13 pm
Location: Netherlands

by Gazelleer

No weight reduction but I think a Shimano FC-R600 compact crankset looks best with the 7800 groupset. Same timeframe, same style. You may keep the Dura Ace bottom bracket.

by Weenie


Visit starbike.com Online Retailer for HighEnd cycling components
Great Prices ✓    Broad Selection ✓    Worldwide Delivery ✓

www.starbike.com



KarlC
Posts: 1028
Joined: Fri Dec 05, 2014 2:08 am
Location: De Portola Wine Trail Temecula CA

by KarlC

Gazelleer wrote:No weight reduction but I think a Shimano FC-R600 compact crankset looks best with the 7800 groupset. Same timeframe, same style. You may keep the Dura Ace bottom bracket.



I read on another forum that there is a R700 also .....

"The R700 was supposed to be between DA and Ultegra. I ride it and think it is more like Ultegra. The R600 weighs more and is more in line with the 105 group as mentioned."

So maybe R700 is another option ?
C64 My Sixty 4 SR EPS 12

eric
Posts: 2196
Joined: Tue Nov 11, 2003 9:47 pm
Location: Santa Cruz, California, USA
Contact:

by eric

Unless the front derailleur is already at the bottom of the slot in the bracket (which is extremely unlikely), it'll slide down.

The difference in radius between 53t and 50t is pretty small.

User avatar
Gazelleer
Posts: 735
Joined: Mon Nov 01, 2004 3:13 pm
Location: Netherlands

by Gazelleer

I have a CR1 with a Shimano front derailleur and compact crank. The front derailleur can be mounted low enough.

sanrensho
Posts: 433
Joined: Tue Aug 02, 2011 5:54 pm

by sanrensho

^^^Same here. No issue with compact or front derailleur.

Regarding crank, if I were starting over, I would probably go Red 22 compact GXP for weight reasons.

crustyshane
Posts: 15
Joined: Thu Jan 15, 2015 12:47 pm

by crustyshane

I recently changed mine to a semi compact crank (11 speed 52/36) on my 10 speed setup. Works a treat and shifts nicely. Paired with 12/30 rear. Makes hills fun too.

Sent from my GT-I9305T using Tapatalk 4

Raineman
Posts: 185
Joined: Mon Oct 06, 2014 2:03 pm
Location: Kent, UK

by Raineman

IIRC your frame has english treaded bottom bracket and the cranks use a hollowtech II spindle. The cranks also weigh about 750g. Any 11sp chainrings will work with 10sp chain so no need to worry about compatability really.

So you could just swap the cranks for some modern shimano ones and that should save you some easy weight (dura ace 9000 ~650g) plus interchangable rings.

If you want to save more weight, SRAM red BB30 with a rotor BSA30 bottom bracket is a good place to start or some proper ww stuff.

KarlC
Posts: 1028
Joined: Fri Dec 05, 2014 2:08 am
Location: De Portola Wine Trail Temecula CA

by KarlC

Ok so it sounds like I will not have an derailleur issue changing to a Compact crank, thx guys !

I have much to learn, as I still don't understand ....

- The differences with Bottom Brackets
- What Bottom Bracket I have. It has 1.37" x24TPI R.H. on it


What do you guys think of these Cranksets ? Will it work with my Bottom Bracket or do I need a new one ? Is it a good WW one to pick ?

http://www.ebay.com/itm/Sram-Red-Carbon ... 19f3aaf839

http://www.ebay.com/itm/Sram-Red-Carbon ... 19f3aaf839

http://www.ebay.com/itm/FSA-SL-K-Light- ... 3aa2b65e34


Any input or other suggestions will be helpful, Thx
C64 My Sixty 4 SR EPS 12

Raineman
Posts: 185
Joined: Mon Oct 06, 2014 2:03 pm
Location: Kent, UK

by Raineman

The required bottom bracket depends on the frame and the crank you want to install. You have an english threaded (BSA) frame. The cranks you are looking at are BB30 so you need a bottom bracket compatible with both. In this case a BSA30 bottom bracket will do, such as this.

Obviously if you choose to buy a different crank you have to make sure it is suitable for your frame and then buy an appropriate bottom bracket to match

eric
Posts: 2196
Joined: Tue Nov 11, 2003 9:47 pm
Location: Santa Cruz, California, USA
Contact:

by eric

You can use some BB30 cranks on a BSA frame. You will need cranks with extra long spindles, and BB bearings with 30mm ID and in BSA thread on external cups. Red cranks used to have short BB30/PF30 only spindles. The ones you linked to look longer (the spider is no longer flat) but I don't know if they are long enough.

KarlC
Posts: 1028
Joined: Fri Dec 05, 2014 2:08 am
Location: De Portola Wine Trail Temecula CA

by KarlC

Here are a few more options that say they have the english threaded (BSA) Bottom Bracket. Still need to do more research on quality and weights. How are the FSA cranks, what ones do you prefer ?

http://www.ebay.com/itm/FSA-K-Force-Lig ... 4634aa84ac

http://www.ebay.com/itm/351315938751?_t ... EBIDX%3AIT

This one is interesting ...

http://www.ebay.com/itm/171685367018?_t ... EBIDX%3AIT
C64 My Sixty 4 SR EPS 12

eric
Posts: 2196
Joined: Tue Nov 11, 2003 9:47 pm
Location: Santa Cruz, California, USA
Contact:

by eric

While I have used FSA cranks in the past I do not like their BBs. The bearings have a lot of drag and the seals are not that good.

I'd recommend a Shimano-compatible crank with Shimano bearings, or an Sram GXP. The GXP design is neat in that there is no bearing preload to set (or to get wrong and roach a set of bearings). The NDS bearing locates the crank laterally and it floats in the DS bearing. It's super easy to install and works well.

The older GXP bearings were not that good but for at least the last three or four years they have been quite good, and inexpensive.

The Zipp cranks use a proprietary crank bolt pattern. I'd be sure that chainrings were available before buying. Also some of them have broken, do a search here. You can get the BBs cheaper elsewhere.

Fairwheel Bikes has a recent crank comparison test, you might want to check it out.

by Weenie


Visit starbike.com Online Retailer for HighEnd cycling components
Great Prices ✓    Broad Selection ✓    Worldwide Delivery ✓

www.starbike.com



KarlC
Posts: 1028
Joined: Fri Dec 05, 2014 2:08 am
Location: De Portola Wine Trail Temecula CA

by KarlC

Thanks for all of the input guys.

Here is another option, I have a buddy that has a nice Ultegra 6700 172.5 50/34 compact he said I can have for cheep. It should be a bit lighter and match my Dura Ace 7800 parts well. Also I am thinking that it will be a direct fit so I will not have to change my bottom bracket.

Any thoughts ?
C64 My Sixty 4 SR EPS 12

Post Reply