Build advice starting from scratch - KTM Carbon 27.5"

Discuss light weight issues concerning mountain bikes & parts.

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DigitalArt
Posts: 38
Joined: Sat Aug 20, 2016 7:30 am

by DigitalArt

Hey guys.

Newbie ere :waving: I turned into a bit of a weight weenie back in 2011 when I installed a carbon set of rigid forks on my Cube and the difference on the trail was night and day :o ever since that ride I have been obsessed with losing bike weight.

I have recently purchased a new 2014 KTM Myroon 27.5" Carbon frame which I am told weighs 1,100g and so my journey begins, but being my first build I don't have a clue what I am doing :lol: :roll:

I hope it's ok to ask all my questions in this one thread and go from start to finish with this build and hopefully you'll be patient with me while I learn as I go along.

SO my first mod and first question is.....

BOTTOM BRACKET & CRANK SET

The original spec of components on the original build were as follows:

Bottom Bracket - Shimano BB71-41A-Set PressFit. 89.5mm with (2.5mm Spacer) and 92mm Shells with 41mm Cup Diameter (74g)

Crank Set - They came with 2 options: Shimano Deore XT M785 38-24 (790g) OR Shimano Deore XT M782 40-30-22 (870g)

What I know so far is that I want to stick with 3 x 10, at the moment I use 3 x 9 on my Cube and I like having the big ring because I have to travel on the road for 30 minutes to get to my local trail centre and I give it the beans 25mph on the way there so I want the big ring for that, that is of course if I understand it right this will allow me to attain a higher top speed with 3 x 10 than 2 x 10.

So I need 3 things to get me started fellas please.

1. Bottom bracket, I am not familiar with this press fit situation. The weight looks great at just 74g, should I stick with the one listed above that was installed on the bike when new?
2. Crankset, 870g for a 3x10, can I get lighter than that for under £250 or again should I stick with the original spec on that one.
3. Finally, I assume I will need some tools to install this press fit bottom bracket (oh er I almost sound like I know what I am on with :lol: :oops: ) any suggestions on an affordable kit to allow me to install / uninstall a press fit BB.

That should be it for now, I get the frame on Wednesday and I'll report back with pics of the build and a spec sheet and weight of everything as I go along.

Cheers :thumbup:

joeg26er
Posts: 122
Joined: Thu Aug 28, 2008 3:40 am

by joeg26er

First - Get a gram scale that goes up to 25 lbs. I say this because you state that you were "told" what your frame weighs.
First rule of weight weenie club is - you have to have a scale that weighs in grams.

Hmm- I ride 11-36T high gear and you can get up to 30-40mph on that set up no problem. Ditch the 3x9

Next SL 2x crank is 450g with BSA BB

by Weenie


Visit starbike.com Online Retailer for HighEnd cycling components
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krzysiekmz
Posts: 978
Joined: Sat Nov 10, 2007 4:23 am
Location: Poland/Toronto
Contact:

by krzysiekmz

As above get a decent scale. This is a WW essential.

Shimano XT BB and crankset seem ok. If you want to keep 3x10 then lighter chainrings/chainring bolts are an option. Getting lighter means more $$$

Second suggestion is to outline your budget.


Chris.
Orbea Oiz - xxxx
MSC Koncept Carbon Di2 - 6955g
Leichtkraft Team Carbon - 6868g.

DigitalArt
Posts: 38
Joined: Sat Aug 20, 2016 7:30 am

by DigitalArt

Morning fellas, thanks for the info :)

OK I have kitchen scales, mini ones that weigh in grams and I also have fishing scales that I use to weigh the bike, I'll check today to see if they are accurate.

I like the sound of the SL 2x crank and the weight even more :D

Budget wise I had £800, I have spent £400 on the frame and I have £400 left now to spend, once that's gone it will be odd component here n there until it's finished which I hope to be around Christmas, as you see I need to spend wisely but if I buy expensive stuff that's OK it just means the build takes longer.

I probably wouldn't want to spend more than £200 on a crankset.

I have been unable to confirm that 2x is lighter than 3x, that is by the products that I am looking at on Chain Reaction Cycles and I cannot find SL crank coming in less than 600g.

If you know of anything around £200 I am all ears, looking to order online today if poss but I will wait for some pukka advice.

Cheers :)

DigitalArt
Posts: 38
Joined: Sat Aug 20, 2016 7:30 am

by DigitalArt

Just an update on this.

I got the frame this morning, she's awesome :o comes in at 1,213g

The frame came with a Ritchey headset and I ordered a bottom bracket and crankset with a park tools bb installation tool.

If the bb and crankset quoted figures are right I should be looking at the 2,057g mark but I will confirm that when I get my parts on the scales for sure.

I do hope these parts fit the frame, the representative said they would, I thought it was bb30 but apparently its bb92, god knows will find out tomorrow :lol:

What I really need now is a seatpost ideally around £50 but I know I am looking at more like £80 for a good one, I had the KCNC Scandium Ti Pro Lite one before that was 167g but I want carbon this time, frame and crank are carbon so wanna keep with the flow.

:thumbup:
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TheRookie
Posts: 926
Joined: Wed Jan 18, 2012 4:23 pm
Location: Midlands, United Kingdom

by TheRookie

Stick with the KCNC seatpost, you'll be paying quite big money for a lighter post (even in carbon) and it would be better spent elsewhere unless you have cash to burn.
Impoverished weight weenie wanna-be!
Budget 26" HT build viewtopic.php?f=10&t=110956

DigitalArt
Posts: 38
Joined: Sat Aug 20, 2016 7:30 am

by DigitalArt

Thanks Rookie :thumbup:

My only concern with the seatpost now is what length? The built bike came with a 400mm one but I am only 5'9" and I was hoping I could get away with a 350mm seatpost but knowing my luck I will buy that and find it's not long enough so unsure if I should take that gamble.

Last night I managed to get the press fit bottom bracket installed with my new parktool press, not sure if I did it right, never done one of these before, but I greased the bb and used the press, left the spacer on and took my time and eased it in, I figured it wasn't rocket science, followed the instructions and it all appears to be well.

I installed the crank next as per the instructions, torqued it up to 61nm and again all seems OK, I just hope it is when I get round to riding it.

Wanted to say thanks to joeg26er for the tip on the SL crankset, its very light and matches the bike perfectly, cheers :thumbup:

Hopefully some pics attached.

Frame - KTM Myroon 27.5" Carbon M: 1455 Performance Carbon Monocoque - 1,213g
Headset - Ritchey WCS Drop In Headset - 73g plus KTM Top Cap, Bolt and Star Nut - 26g
Bottom Bracket - Race Face X-Type Press Fit BB Cups 41mm BB92 - 94g
Crankset - Race Face Next SL 10 Speed 100% Carbon Double Chainset Ti Spindle 170mm 40.28t - 526g plus Race Face Crank Arm End Boots - 17g
Total Weight - 1,949 kg

Mods will be at a much slower rate now but hope to get a seatpost sorted next week.
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TheRookie
Posts: 926
Joined: Wed Jan 18, 2012 4:23 pm
Location: Midlands, United Kingdom

by TheRookie

A proper WW cuts the post down for 100mm insertion and no more.....

Measure on an existing bike your centre of BB to saddle rail distance and you'll know what length seatpost you need.
Impoverished weight weenie wanna-be!
Budget 26" HT build viewtopic.php?f=10&t=110956

DigitalArt
Posts: 38
Joined: Sat Aug 20, 2016 7:30 am

by DigitalArt

Thanks for the tip mate :)

DigitalArt
Posts: 38
Joined: Sat Aug 20, 2016 7:30 am

by DigitalArt

Hey guys.

Just wanted to update me thread with me latest weights.

Bike is nearing completion now, all that is needed are mech cables and I should be ready to ride, oh and some frame film protection perhaps.

Image

All figures in green are confirmed prices and weights, figures in black mean they are in the post and are advertised weights but in my experience things are generally heavier once I get the items on the scales at home.

With just the brake and cable weights to add now I think I will be looking around 9.4kg when fully built. Would have been nice to get it into the 8kg mark but I really don't know how that would have been possible or where I could have saved any more weight.

I'll add the final weights and some pics when she's ready to roll.

Thanks to everyone who gave me ideas and links, without your help this build wouldn't have turned out the same.

Cheers :thumbup:

nunokas
Posts: 148
Joined: Tue Aug 26, 2014 3:18 pm

by nunokas

Very nice build. I want to see some pics ready to roll :thumbup:

The 8kg mark is totally possible but for that you have to go a bit more "exotic on the wallet" :mrgreen:

Here's mine:

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by Weenie


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

www.starbike.com



DigitalArt
Posts: 38
Joined: Sat Aug 20, 2016 7:30 am

by DigitalArt

Wow nunokas :o awesome build, why couldn't I have built mine like that :lol: :oops:

Excuse the poor pics, I have a blackberry :oops:

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So 9.31kg and I have lockrings (20g) grips (21g) bar end plugs (54g) and yeah that should see me complete :D

Might even get my first run tomorrow if my bits turn up.

Final weight should be approx 9.4kg give or take an ounce or two.

I don't know what else I could have done to save weight :?: I am a bit disappointed in the seat as that is 250g but cash is all expelled now so it was either get that and ride now or be off the road even longer waiting and I can't wait any more, need to get some miles in.

Lovely looking bike in all orange, I would have had that but the frame was £100 more.

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