SRP bolt kit for DA 2004 rear mech DR-7800

Discuss light weight issues concerning road bikes & parts.
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Tippster
Posts: 2520
Joined: Fri Dec 12, 2003 3:11 pm
Location: Frederica (Denmark)

by Tippster

Thought I'd share with you the weights from having stripped down my new Dura Ace 7800 rear mech.

Pivot bolt (DA) 10.38g
Pivot bolt (SRP - Al) 5.94g

Pullet wheel bolt x 2 (DA) 3.99g
Pullet wheel bolt x 2 (SRP - Al) 1.34g

Cable bolt (DA) 2.37g
Cable bolt (SRP - Ti) 1.50g


Total savings of SRP bolt kit for a DA 10 speed DR-7800 2004 rear mech 7.96g. For the obsessives, you could switch the Ti cable bolt for an Aluminium one and save a further 0.7g.

For the record before tuning 181.66g. Without barrell adjuster 177.42g.

I'm running my DA 7800 mech on a mtb with XT shifters. The shifters have barrell adjusters, so the adjuster on the mech gets dropped.

Next stage is to replace the mech plate with Carbon Fibre. Expected saving 3g. Expected final weight 165g.

BdaGhisallo
Posts: 1797
Joined: Wed Mar 17, 2004 1:38 pm

by BdaGhisallo

All that work for 7.96 grams!!

I think you need help. I know that this is a weight weenies forum but I think you have taken it too far. Get help before you start filing down the tread serrations on your tires to save 3.458346 grams!!!!!

by Weenie


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eurorider
Posts: 555
Joined: Fri Oct 24, 2003 12:56 am
Location: Toronto, Canada

by eurorider

that's very informative

thanks tippster for the thorough details :)

simonali
Posts: 35
Joined: Fri Jan 30, 2004 2:23 am
Location: UK

by simonali

BdaGhisallo wrote:All that work for 7.96 grams!!

I think you need help. I know that this is a weight weenies forum but I think you have taken it too far. Get help before you start filing down the tread serrations on your tires to save 3.458346 grams!!!!!


Seconded. All that for a few grams and you end up with a less reliable component that probably doesn't work as sweetly as before.

To save the same weight, why not just pop a zit before you ride your bike! :lol:

Racing Aardvark
Posts: 640
Joined: Thu Jan 15, 2004 1:44 am
Location: Boulder, CO

by Racing Aardvark

simonali wrote:To save the same weight, why not just pop a zit before you ride your bike! :lol:


I prefer to take a good poo before mountain rides and drop a pound! ;)

Mr_Potatohead
Posts: 125
Joined: Thu Jun 10, 2004 5:31 pm

by Mr_Potatohead

Racing Aardvark wrote:
simonali wrote:To save the same weight, why not just pop a zit before you ride your bike! :lol:


I prefer to take a good poo before mountain rides and drop a pound! ;)


you actually weighed it? Or you weighed yourself before and after?

I myself like to leave my prosthetic brain at home, saves 7 or 8 pounds.

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cadence90
Posts: 1694
Joined: Sun Dec 14, 2003 1:52 am

by cadence90

It seems like some "weight weenies" prefer to spend their time in the bathroom, rather than in the garage or on the road.... :P
What's wrong with Tippster posting these weights?
I agree that I wouldn't do it to my derailleur for that savings, but there is a whole listing section on hardware, and there are people that go gaga over carbon bottle cage bolts, mech. clamps, etc....those save less weight and are possibly even riskier than Tippster's subsitutions. :wink:
"Gimondi è un eroe umano, che viene sconfitto ma che continua la sua corsa fino a tornare a vincere." - Enrico Ruggeri

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Mav54
Posts: 32
Joined: Sat Mar 27, 2004 5:58 pm

by Mav54

Seconded. All that for a few grams and you end up with a less reliable component that probably doesn't work as sweetly as before.


I bought a bike on ebay 2 yrs and 7k miles ago with a SRP kit.
Running great, and very light.
No reliability problem!

gentri
Posts: 63
Joined: Sat Jan 10, 2004 5:34 am
Location: Hawaii

by gentri

That was very good and very precise in paying attention to details. I'm glad that there are people other than myself that understands and appreciates modifications.
I guess other people would rather use the bathroom and bash others.

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Tippster
Posts: 2520
Joined: Fri Dec 12, 2003 3:11 pm
Location: Frederica (Denmark)

by Tippster

Finally got my Carbon mech plate for my rear mech.

Mech plate (DA) 7.30g
Mech plate (CF) 5.26g

Very pricey to shed just 2.04g. But looks the muts nuts!
The level of service from Steve at Fibre Lyte was excellent.

Complete weight 166.56g
Tuning applied:
SRP bolt kit
replaced Ti cable bolt from SRP with an Al bolt from redmist
carbon mech plate from fibre lyte
removed barrell adjuster (already have adjusters on XT shifters)

10.86g saved - cost £19 (£1.75/g) - cheaper than Ti bolt tuning

Nino has done some interesting pulley wheel tuning with a drill. I've seen pics of Deore pulley wheels, drilled to save 9g!

I realise not all visitors and/or members on this site are ULTRA weight weenies. For those that are, or considering tuning their bikes, I hope the info has been helpful.

---------
Tippster
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Joel
Posts: 751
Joined: Fri Jun 13, 2003 1:43 pm
Location: Belgium

by Joel

The Record derailleur pulley wheel bolt are standard drilled! I think they are steel. Is a drilled Al bolt strong enough?

by Weenie


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Tippster
Posts: 2520
Joined: Fri Dec 12, 2003 3:11 pm
Location: Frederica (Denmark)

by Tippster

The SRP pulley wheel bolts are Al drilled right throught the centre with approx 1mm diameter.

stock are solid steel

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