650B build advice need

Discuss light weight issues concerning mountain bikes & parts.

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stormur
Posts: 1173
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by stormur

I decided to switch cyclocross bike for 650b...

Goal is sub 10kg ( frame weight 1200g in size L ) , but bit more over won't make me unhappy. I won't race, it'll be rather gravel/cross country/ forest paths leisure bike for half/all day long trips.

Have already frame : 27.5", tapered HT (11/8:1.5) , rear dropouts : QR. Geo for 100mm fork.

My main concerns are
A. Fork : found nice deals on SID RL, but it's QR. 30% € more gives me DT DL fork with thruAxle. I also opened for other options. Is there real life advantage of thru axle vs QR ?

B. Brakes : I know to avoid anything Sram like a plague in that matter, Q is is any reasonably light/ well performing /reasonably priced other than f.e. Shimano XT ?

C. Drivetrain : If it will be 2x11 than ( from CX experience ) I'd like to have something like 28-42/11-32 gearing in MTB ( possible ? ) , or 1x11 - but Q is how much I have to sacrifice to go (100g ? ) lighter ?

D. Wheel : what's reasonable weight for XC rides / 85kg rider ? I can buy "factory", I can build by myself ( which basically prefer )

Any EXPERIENCE BASED advices welcomed :)
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aspms
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by aspms

A. If it's not racing bike and more likely budget build, than QR is fine for such a saving as 30%. But have driven both latest SIDs and latest DT Swiss OL fork, I would definitely go for DT, it just feel much better in terms of small bump compliance. Maintenance for both of them is really simple.

B. Never had any problems with Sram top tier brakes, in fact they have best shaped levers for my small hands. Currently riding M8000 on my racing bike and also like them. Brakes to stay away from I would say are Formula, be it R1 or RX different generation all of them have leaked from master cylinder and damaged clear coat on carbon bars :evil:

C. I doubt you would currently find any crankset with such ratio, maybe some Truvativ XX from old stock or some other second hand options. But it's not a problem to put on aftermarket chainrings on any crankset. I would go with something with BCD104 for wider choice of chainrings.

D. Reasonable weight would be ~1.5-1.6kg. For rims I can recommend Stans Crest (mk3 with wider profile), BOR 333 wide+, WTB KOM i23, for hubs- DT with ratchet.
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CulBaire
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by CulBaire

A) The SID is a capable fork, it does suffer from lack of small bump sensitivity though something I miss about dual air. I find the 15mm axle seems to track a lot better than QR on the same wheelset particularly being a bit heavier (85kg).

B) Shimano XT/XTR, Formula R1/R0 or for something more expensive like Magura - I have had good experiences with all of them, I wish I could say the same for SRAM (although my experience is limited to older models).

C) Depends on where you ride, if you can get away with 1x11 w/ a 45t on the back then the weight savings will be reasonable. In more mountainous terrain you cant go past 2x11, you'll find most offer 26/40t or 26/38t, ratios which is no issue but I will echo the comment above go for something 104BCD as there are plenty of options available. :thumbup:

D) Wheels these days 1.4 to 1.5kgs will get you something quite reliable - strength comes from the build so a custom build might be worth while if you are a bit harder on wheels - people seem to be singing praises of Carbon MTB wheels at the moment. :noidea:

:beerchug:

stormur
Posts: 1173
Joined: Tue Aug 12, 2014 3:50 pm
Location: FIN

by stormur

Thanks !

Forks decided ( and bought ) : DT Swiss OPM DL - 27,5" ( edit : Marzocchi cancelled ). Fork has good feedback, and fits Italian frame color ;)

I decided to make "budget" build : in my understanding: I'm eager to pay not more than 40-50% of MRSP. I have time to search, so it will be "insanely" cheap :)

For now I spent 600€ for frame ( Wilier 101 ) and fork together... Naturally all components are/ will be brand new, with warranty.
I believe I'm able to build <10kg for <1500€ . From other side, I don't want extra light components sacrificing reliability ; bike is inteneded for long lonely trips, so has to be VERY reliable.

Where I live all can see, ... not so many mountains here, rather 1001 hills, rocks, gravel, roots... Need something more comfy than CX bike, and able to go bit further.

Double chainset is a "leader" now , something like 28/30 - 40 with 11-36 will be absolutely enough.

Generally I like "homogenic" components ( same brakes as drive ) , so Shimano XT/XTR mix is main idea currently - but it depends from deal I can find ;) .
Go to Heaven for the climate, Hell for the company.
Mark Twain


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bikewithnoname
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Joined: Tue Sep 22, 2009 1:29 pm
Location: Paris

by bikewithnoname

My 2pence on this is:

A) QR hubs are going the way of the dodo, I would personally go for the QR15 as it means your wheels won't be redundant in 2years when you look for your next upgrade

B) SRAM guide brakes are actually rather good, have them on my Habit and have been impressed (elixirs and juices are utter crap)

C) The decision on 2x or 1x should really be governed in the terrain you ride and whether you're an XC guy at heart and like more of a close ratio riding set up

D) my biggest recommend is whAtever you get make sure they are convertible hubs as the way things are going with boost you'll want your wheels to last your next upgrade in frame or fork so hubs like DT which you can convert to any axle type are a good idea. I will add that in my experience Stans Crests are the work of the devil, whilst they are light they are a nightmare to get tyres on and off, I'd go for WTB personally
"We live in an age when unnecessary things are our only necessities." Oscar Wilde

stormur
Posts: 1173
Joined: Tue Aug 12, 2014 3:50 pm
Location: FIN

by stormur

For now I have 2 forks : DT OPM O.L. 27.5 and Marzocchi 320LR. Both 15mm TA . Weight difference is ... 60g.

I wonder which to keep . Only difference I notice ( :mrgreen: ) is travel adjustability in Marzocchi ; as standard it's 100, adjustable to 80 or 120 ) .
For me both are... black :roll: Which to keep , which to sell ???

Drivetrain/ brakes : I'm leaning towards XT , just left to decide 10 or 11 spd. I would prefer 10. It's not about weight, rather ice&snow clogging in cassette.
Go to Heaven for the climate, Hell for the company.
Mark Twain


I can be wrong, and have plenty of examples for that ;)

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

by TheRookie

You should be able to hit 10Kg very easily, my old HT (1735g frame) was circa 9.3Kg (cost circa £500 to build using mostly used parts) and my FS is 10.1Kg (stared as a frame swap).

1x will lose you nearly half a kilo, the budget lightweight route is 1x10 using a Suntour MX3 cassette (11:40 or 11:42) then you can probably get a decent XT rear mech and shifter used for not too much, I'm using an XTR 9 speed mech (182g with lightweight jockeys) carried over from my 1x9 setup and an SL-R780 Ultegra shifter to work the 10 speeds.

Formula RX brakes don't give away much to the R1's in terms of weight but are quite a lot cheaper I'm running OE spec R1s (R1 lever and RX calliper), use lightweight discs like Ashima or Alligator.

Key with any lightweight build is the detail, small details can add a shed load of weight you just splashed big money on saving!
Impoverished weight weenie wanna-be!
Budget 26" HT build viewtopic.php?f=10&t=110956

Cleaner
Posts: 213
Joined: Wed Oct 28, 2009 7:13 pm

by Cleaner

For the wheels I would suggest considering Easton Arc rims with DT Swiss hubs. I jusy built a 650b set using 240s hubset and they are lightweight for an aluminum rim wheelset. I used the 24 mm wide version of the rim which bucks the current trend but is the lightest option and supports up to 2.4" width tires without issue IMO.

http://forums.mtbr.com/wheels-tires/easton-arc-24-650b-28-hole-build-1014779-post12680492.html?highlight=#post12680492

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

by TheRookie

Not sure I'd call 425g/rim that light! My 26" rims are 325g and my new 29er rims are 440g.....
Impoverished weight weenie wanna-be!
Budget 26" HT build viewtopic.php?f=10&t=110956

stormur
Posts: 1173
Joined: Tue Aug 12, 2014 3:50 pm
Location: FIN

by stormur

Budget is TIGHT. I decided to establish 1500€ as absolute max ( and this time to not cross the border ;) ) .
TIll now frame & fork took around 1/4 of the weight ( 1200g frame + 1570g fork incl front axle ).

Used parts are not in the consideration. Same 9 spd. 11 spd is OK, but 10spd is very OK. Everything must be new, or new taken from the new bike. I'm buying in outlets exclusively, so it require time and limited choice of components.

Problem which I see in 1x11 is chainring size. I need somethig like 36 -38, where "standard" max is 32 :( . Buying crank and chainring incease cost noticeably. 500g saving is .... 300g in real life ? ;) / - shifter, cable&housing, FD, small chainring + heavier chainring, guide, bigger range -heavier cassette .../ .

From own experience, going below 450g for the rim ( being 85kg light ) is not the smartest choice if it's intend to ride not to be photographed only.
Go to Heaven for the climate, Hell for the company.
Mark Twain


I can be wrong, and have plenty of examples for that ;)

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

by TheRookie

I'm 86Kg and ride 325g Stans Alpine (26" admittedly, so 650B equivalent would be about 350g, their weight limit 75Kg....ahem I'm about 90Kg ready to ride with full hydration pack) have been using them weekly on local XC routes, urban kerbs and steps and trail centres now for 2 and a half years, after 2 years they needed a minor true up.

NW rings of 36T are readily available, then no need for a guide. Weight saving is minus one ring (circa 40g - more for steel), shorter bolts (3g), no cable (inner and outer - 8g plus 30-50g depending on routing), no front mech (160g) and no shifter (130g) so 360-380g compared to a 2x, more compared to a 3x.
Impoverished weight weenie wanna-be!
Budget 26" HT build viewtopic.php?f=10&t=110956

stormur
Posts: 1173
Joined: Tue Aug 12, 2014 3:50 pm
Location: FIN

by stormur

My experience in rim weight says something different ;)

Another thing is weight : I'm eager to sacrifice few hundred grams for versatility. Do decision has been made : 26-38 front, 11-36 rear, 10 spd.

Magura Mt 4 brakes, Storm SL 160 f&r brakes.
Go to Heaven for the climate, Hell for the company.
Mark Twain


I can be wrong, and have plenty of examples for that ;)

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

by TheRookie

stormur wrote:My experience in rim weight says something different ;)

Or maybe its a reflection in the quality of build!
Impoverished weight weenie wanna-be!
Budget 26" HT build viewtopic.php?f=10&t=110956

by Weenie


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stormur
Posts: 1173
Joined: Tue Aug 12, 2014 3:50 pm
Location: FIN

by stormur

I never re-trued my ( build for myself and for others ) wheels ( from 1100 to 1600g ) . It didn't happened yet, and it won't. And never had factory wheelset with "mine" build accuracy ( tension difference & trueness ) : even sets with MRSP 2500€...

You have to true your wheels time to time...Well,..... conclusion/ reflection is yours :)
Go to Heaven for the climate, Hell for the company.
Mark Twain


I can be wrong, and have plenty of examples for that ;)

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