Aluminium frame + Dremel = How many grams lost?

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

Moderator: robbosmans

SABARRAS
Posts: 55
Joined: Sun Jan 29, 2017 1:04 pm

by SABARRAS

Hello everyone,

I'm new to the site and would like your advice on a bike build that I'm working on.

I bought a 51cm Planet-X Galibier SL aliminium frameset like this: http://www.planetx.co.uk/i/q/FRPXGAL/pl ... d-frameset

They claim a weight of 995g but the actual weight was a rather disappointing 1135g.

I have a SRAM Red Etap groupset and intend to respray it so I was going to see how much unnecessary weight I could remove without damaging the structural integrity.
I suspect that removing the cable guides with a Dremel and the pewter head badge will get me close to 1100g.

After removing the paint, I was going to Dremel/file the bulging welds flat, remove all the weld ridges (without digging too deep), the front derailleur support can be slimmed down a bit (the area welded to the frame)

Then I noticed that inside the head tube and bottom bracket, there are some holes that line up with the top and down tubes, it looks like I could remove quite a lot of aluminium if I carefully make those holes larger - the material within the tube intersection welds seems unnecessary. Then aluminium or titanium hanger bolts might save a few extra grams.

Has anyone every attempted something like that?

What would your estimate of the weightloss be after performing all the above?

audiojan
Posts: 795
Joined: Fri Jan 27, 2006 1:38 pm
Location: New Hampshire

by audiojan

If you're unlucky you can save 1135g. I wouldn't start chopping it up without understanding structural integrity.
"Suddenly the thought struck me; my floor is someone elses ceiling" - Nils Ferlin

by Weenie


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

www.starbike.com



SABARRAS
Posts: 55
Joined: Sun Jan 29, 2017 1:04 pm

by SABARRAS

audiojan wrote:If you're unlucky you can save 1135g. I wouldn't start chopping it up without understanding structural integrity.

Of course! There is a risk of messing up.
The welds on the frame look well done with generous fillets all round, they are actually quite smooth already, I 'm talking about removing the parts where there are imperfections and clearly excessive amounts of weld - not digging in too deep.
I've done a bit of research on weld smoothing and if done correctly, it can actually strengthen the frame by removing "stress raisers"
https://www.hera.org.nz/Story?Action=View&Story_id=1092
http://singletrackworld.com/forum/topic ... ooth-welds

User avatar
BRM
Posts: 817
Joined: Sun Mar 16, 2014 3:43 pm

by BRM

Your assumption that you can shave 35 grams we can discuss, but when we go with that thought:

What is 35 grams? Is it worth the hassle? Don't come with unintelligent text that this is WW.
Be real. 2 average envelopes with 2 A4 letters in it weight more . . . . .

Thats the weight you're bothering.

Imo, pretty senseless. Because you never ever will notice such a difference in weight.
Stop looking through tubes, try to see the total picture of things, please.

bm0p700f
in the industry
Posts: 5777
Joined: Sat May 12, 2012 7:25 pm
Location: Glermsford, Suffolk U.K
Contact:

by bm0p700f

If you want a lighter frame buy a lighter frame.
You will spend hours and remove 35g. You have potentially weakened the frame for what exactly.

User avatar
F45
Posts: 1077
Joined: Wed Jun 08, 2011 6:08 am

by F45

I would drill the seatstays and seat tube. Those tubes are almost superfluous anyway.

SL1
Posts: 40
Joined: Fri Nov 04, 2016 3:43 pm

by SL1

Are you planning to strip the paint off before re-painting it ? Even if you do that. a new primer, paint job and lacquer could easily result in adding more weight than before.

Once you cut the cable guides off, the frame will be electric compatible only and it will effect the resale value if you try to sell it (yes that day will come). Planet X carbon frames dont hold much value as it is. Alloy frames even less.

It's alot of work for such little savings. Do it for aesthetic reasons not weight saving.

If you bought the blue, i think the head badge and blue paint look quite snazzy. I'd keep those.
Last edited by SL1 on Mon Jan 30, 2017 9:13 am, edited 1 time in total.

User avatar
LouisN
Posts: 3509
Joined: Mon Feb 19, 2007 3:44 am
Location: Canada

by LouisN

Bad idea. Wrong thinking.

It's actually a very nice weight for such a frame. Close to the lightest Cannondale CAAD's, and Trek Emonda ALR's of this world.
Build the thing, and ride it.
There are alloy frames ( and CF too) that have heavy paint coatings. Not shure about the Planet x one.
Maybe you can strip the frame and have it powder coated. Don't know if the heating process can harm the aluminium or welds, as I am not a tech specialist. The fork, you can alos gently strip it and give it a light coat of clear or wax, as it's been done here ( 303 finish comes to mind).
The other weight savings you will have fun to "gain" well, is all the rest of your build :beerchug: .

Louis :)

Marin
Posts: 4035
Joined: Wed Jan 22, 2014 11:48 am
Location: Vienna Austria

by Marin

Don't do it, the frame is very light already.

If it's painted you could remove the paint but then you'll have to deal with corrosion.

Claiming a sub-1kg weight is stupid by Planet X.

SABARRAS
Posts: 55
Joined: Sun Jan 29, 2017 1:04 pm

by SABARRAS

Thanks for your replies. The consensus is clearly - DON'T DO IT!!

I thought there would be more curiosity here about what is possible, you all seem very sensible but you are probably right, I doubt that I could remove more than 50g in total.

I'm going to strip the frame and remove the gear cable guides for sure, then respray it in my own choice of paint job, I'm not bothered about selling it later.

Having said that, I will keep an open mind when I inspect the bare aluminium.

lone wheeler
Posts: 541
Joined: Mon May 22, 2006 11:34 am
Location: Dubai, UAE
Contact:

by lone wheeler

Looks a decent frame and forks for the price, any pics of it in the real world before you mess around with it?

huffington
Posts: 17
Joined: Sun Nov 29, 2015 3:29 pm

by huffington

take a look at this, they used to do it in the 70s and 80s, but those components were already very thick and heavy, and they did it on stuff like levers, derrailleurs, chainrings. I wouldn't do it to a frame, it could go wrong

SABARRAS
Posts: 55
Joined: Sun Jan 29, 2017 1:04 pm

by SABARRAS

lone wheeler wrote:Looks a decent frame and forks for the price, any pics of it in the real world before you mess around with it?
Yeah it looks good (Not my bike by the way)
Attachments
DBCLNECSHOWBIKE40_P1.JPG

SABARRAS
Posts: 55
Joined: Sun Jan 29, 2017 1:04 pm

by SABARRAS

huffington wrote:take a look at this, they used to do it in the 70s and 80s, but those components were already very thick and heavy, and they did it on stuff like levers, derrailleurs, chainrings. I wouldn't do it to a frame, it could go wrong
Ha ha, all those new nooks and crannies to drive you mad when cleaning.

I found this:
http://www.bikeradar.com/forums/viewtop ... t=12956986

and This:
http://singletrackworld.com/forum/topic ... ice-needed

and this:
http://forums.mtbr.com/frame-building/g ... 23593.html

It does seem good practice to flatten any ridges and bumps - my frame appears to have been constructed using the double pass welding technique.

by Weenie


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

www.starbike.com



mattr
Posts: 4671
Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

Just be careful not to put too much heat into the weld, or any gouges.
Doubling up on HAZ and adding stress risers isn't a good idea.

Post Reply