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This may be a naive question, but since I've been an MTB and road cyclist, I've started to wonder why the weight difference between the two isn't bigger.
Take Mavic rims. The new Open Pro's are only 24g lighter than the XC621 rims (430g vs 454g), and the latter are even cheaper. Surely the XCs are a bit stronger too...?
And I also remember coming across the 2018 Specialised Epic frame recently, which was for a short while lighter than any of Specialised road frames.
Looking at the Genesis range (not the most representative choice I know, but at least they state all the weights on the sight, and they look nice), the top-of-the-range Zero Disc road bike is 8.2kg and the Mantle XC bike is 10.1kg. Switch out the forks on the Mantle for some rigid's and it'd probably be down to 9kg, and that's with 2.2" 29er tyres.
So I imagine you could get a rigid 650b mountain bike down to a similar weight as a road bike of the same price. And it should be significantly tougher...
Obviously I'm missing something here, but what is it?
I think what you're missing is what a good road bike weighs. A hint - it's nowhere near 8KG!
That would explain the top end stuff, but not Mavic or Genesis weights...?
UCI minimum for a road bike you race on is 6.8kg. Most manufacturers have bikes in their range that are well under that, up to 1kg under in some circumstances. My not mega expensive and size XL road bike is just under 8kg.
So I guess they are light, your challenges was you looked at Genesis and not a "proper" road bike manufacturer. Have a read here:
Also, open pro are a touring rim built for strength. People don't use them on race bikes for racing.
If you remove the terms road and mountain and just compare all bikes they follow a very similar design. Most will be 3 triangles with 2 of them incomplete. 2 wheels, gears etc. The only real difference in a mtb is things are generally bigger but being hollow tubes the weight increase isnt that much and road bikes need to be strong enough to take both a lot of pedaling force and the weight of a middle aged fat bloke riding them so still need some mass.
Dont get me wrong i have ridden a 6kg road bike and a 30kg emtb so there are exceptions.
Some companies have zero inspection / zero quality control
https://www.specialized.com/us/en/safety-notices
https://www.merida-bikes.com/en_int/recalls-1920.html
Is lighter all its cracked up to be?
They both need to support 100kg fatties
Open Pro's may not be racing rims but they aren't touring rims either. Something like the Mavic A719 is and then the weight does jump up, to nearly 600g.
You could also take the Mavic CXP Pro for comparison, definitely meant to be a fast road rim, and that's 470g, about the same as mid-range Mavic XC rims. But it's aero so that explains that.
I'm aware that a good road bike weights a fair bit less than a Genesis Zero, but the Genesis Mantel I was comparing it with is hardly top end either -- it's still running XT gears, not electronic stuff. So it seems a fair comparison.
I think a good comparison would be something like this Focus Raven rigid thing to a nice £3000 disc-brake road bike. I don't imagine there would be much in it weight wise.
Cxp is a cx/ gravel rim.
And the raven to a nice disc road bike would be at least 2 kilos.
My bog standard Spesh Roubaix from several years ago has an on-the-road weight of sub 8kg. At the time the cost was £1600 so really nowhere near top end.
Once you go down a particular design route then there isn't a huge difference in weights, either frame or components. I've a Cotic Solaris in large, my wife has one of the last 26" Souls in extra small. With identical componentry and build, except for the fact that I've 29er rims and tyres rather than 26", there's less than 500g difference in weight.
A mate is obsessive about how much his bike weighs - I think the lightest bike he had was under 6kg, possibly closer to 5.5kg, the downside is that he isn't exactly lightweight and the bikes he picks aren't up to the job of handling that amount of timber.
TBH the only significant differences between XC MTB and road are tyres and forks. Most of the rest uses the same materials and technology and is almost interchangeable.
It's the disc brakes, there'd be more of a difference without them.
Otherwise the 2kg example you mentioned sounds about right to me when you think of the heavier MTB-specific bits - as he says it's just the fork (1kg or so) and tyres (300g each?) that have a big differential.
Yeah. Without discs I'd expect nearer 3 kilos. Or more.
I mean if you go absolute bleeding edge production HT MTB to bleeding edge road (no discs) it's still around 3 kilos.
Looking at a 2017 Spesh Roubaix for just over £3000, that comes in at over 8kg, so the same weight as the rigid Focus:
http://road.cc/content/review/214587-specialized-roubaix-expert-2017
Similar for a Cannondale Synapse -- that's just under £3000 grand and 7.5kg.
In both cases you get a bike pretty much the same weight as a rigid 29er of the same price, once you take tyres out of the equation.
So I guess I'm surprised the frame, much longer rigid forks, rims, cranks, handlebars, seatpost, seat, all those things that take far more of a beating (even) on an XC bike than a road bike, don't give you a load more of a weight difference weight
BTW, I don't think Cxp Pro are CX rims... internal width is only 15mm, and they don't rate them for tyres above 28mm
lustydAlso, open pro are a touring rim built for strength. People don’t use them on race bikes for racing.
They might not be raced anymore but they are still very light rims by road standards. The new ones are even butted between the spokes (and UST, disk brake only etc). They're not a touring rim by any stretch, touring rims are often 800g+ (a lot of that is to last tens of thousands of miles of rim braking).
Even comparing like for like, Stans Crest Vs Alpha, the crest is substantially lighter.
I think a lot of the difference in rim weight is down to the size of the tyre. A 23mm tyre transfers bigger peak loads to the rim than a 2" tyre cushioning most of them. That and maybe the strain the bead puts on the rim at higher pressures?
Even with factory wheels, if you look at kysriums and crossmax wheelsets they're very close in weight (and for the record! a set built with open pros would probably be lighter)
I have a number of theories about why the weight differences isn't bigger.
The minimum strength needed for fork, rims and frame isn't that different between the 2 disciplines. Mountain bikes probably hit square edges more often but than road bikes hit square edges but when they do it's exactly the same sort of collision. However 25mm tyres are alot less of a shock absorber than even say 2 inch tyres. Suspension forks increase leverage on the frame but reduce impact force
Pedaling forces are the same for both and I wonder how much frame weight is about lateral stiffness as opposed to strength
The lengths of the frame tubes are similar. We might be at the point where reducing wall thickness makes bikes to vunerable to to dents and buckling
Or the UCI minimum weight means we are not trying
You have read about the sub 6 lb (2.7kg) road bike with 2 brakes and front and rear derailleurs
https://www.redbull.com/gb-en/check-out-the-worlds-lightest-custom-road-bike
BTW, I don’t think Cxp Pro are CX rims… internal width is only 15mm, and they don’t rate them for tyres above 28mm
Yeah, thats mavic for you. Still using narrow rims and 20 year out of date etrto recommendations for tyre sizes. Don't know anyone who uses them on the road, unless they are provided on a stock bike.
Also, mavic rims are a really really really bad example. Their rim range has been hammered over the last 10-15 years so they can promote their system wheel options. The outgoing open pro has a pretty much unbroken chain of design with minimal changes since the open 4 rim, which i was riding in the mid 80s.
Mavic make heavy rims.
And why do you keep looking at specialized road bikes? Not particularly known for making light road bikes....... especially when you start looking at the roubaix, which is a do anything road/trekking/comfort bike. With all the related extra weight. The Raven you are comparing it with isn't even an XC race bike, it's a specific bike for a specific job.
A quick flick through the canyon website has 3 bikes at the same price. (about 3800€)
MTB at 9.1
Disc road at 7.6
Road at 7.1
Which isn't far off what i'd expect at that price.
Fair enough about the Mavic rims. They have significantly widened most of their stuff this year though (or perhaps it was last year, I don't know). The Open Pro is 19mm now I think. Not sure why they left that Cxp down at 15mm though.
As for the Specialised, I only really looked at one (the Epic) before whitestone brought theirs up. To be honest though, I still find the Canyon weight you mention there a bit surprising. I don't feel like 1.5 kg is much extra weight considering it gets you big wheels and suspension.
What ampthill says make a lot of sense to me. And perhaps that's basically what you meant before, ghostly, when you said beyond forks and wheels everything -- tech and materials -- gets somewhat similar?
That crazy 2.7kg bike is another creature though. Is there a comparable hill-climbing mountain bike that's been made?
The CXP is a ~15 year old rim family, just had minor tweaks and new stickers.
And yes, once you get past the tyres and forks, there is very very little difference.
Even with the uci weight limit, pro bikes with deep wheels and sturdy stems are regularly nearer 7.5kg
TLDR
A road rim has to resist massively higher tyre pressures than a mtb rim and also have a braking surface (for rim brake ones anyway)
A certain amount of structural integrity is required for anyone who's wanting to ride the bike for any amount of time and not have it drop to bits the second you have a small off or crash and have to buy a new frame and forks.
Also consider most bikes bought aren't disposable race day only bikes that can be immediately replaced by a sponsor, they need to be built to last for most people, and the slight weight penalty for the average Joe is a lesser evil to contend with.
Pick an isolated 2kg weight up, then tell me there's not much difference. Or put some road tyres on a mountain bike and appreciate how critical your rubber is.
The think having read this thread wheels are an interesting point.
I’ve got DT Swiss E1900 wheels on my mtb which are considered particularly light wheels. They have a 30mm external width and 25mm internal width, and are pretty strong wheels built to take abuse (27.5” diameter). I think they come in around 2kg for the set, maybe just under.
I’m in the process of buying a Cannondale Caad12 105 Disc which comes with Maddux RS2.0 wheels which are much narrower than the e1900s are you’d think don’t need to be built to take as much abuse. Yet they weigh about 2kgs as well.
Neither wheelset are high end in either discipline so I’m not comparing high end mtb with low end road either.
Having looked online I think for £300 to £400 I can find wheels that’ll drop 500g off the wheel weight for the Maddux and maybe that would be a lot more expensive to do with mtb stuff.
Those Cannondale wheels are low-end, your e1900s are mid-range (had a pair myself).
An equivalent OE non-aero road wheelset would be about 1,600g.
I agree mattyfez, but surely that should apply to MTB and road bikes too, so the weight difference would remain the same?
And joat, I certainly agree that 2kg is a big difference, and that tyres would change everything. The reason I started this thread though is that pretty much all of that 2kg seems to melt away once you make an XC MTB rigid with skinny tyres.
And I suppose that question came up as I've been wondering if I really need a road bike.
It seems like a nice light rigid MTB, with a 650b at the back and 29er up front, and perhaps some Jones loop bars or something with lots of hand positions, would be pretty capable of road (I only ride a rigid 29er now anyway), but a quick change to 700c wheels would make it a pretty fast road bike too
The front end would drop with the 700c wheels, with them being the same size. The back end could be pretty short, like 420mm, so about the same as an endurance road bike. The real problem is gearing I guess.
the only significant differences between XC MTB and road are tyres and forks.
Exactly the reason. Put on some carbon rigid forks (about 300g more that road fork) and some light XC tyres (about 600g per pair heavier) and the difference is less than 1kg. Some MTB stuff is lighter too, flat carbon bar versus drop bar for example.
If you look at things more carefully:
Road bars have more material in them as they're longer tubes once you take into consideration the drops, so spec for spec will weigh more.
The same comment applies as stated above about wheels too.
Madux road wheels are like a set of bogo Alex rims or Mavic 319's on OE formula or Deore hubs, defo not a factory DT Swiss build.
Also generally less chain rings & mech's on a MTB saving more weight.
Mavic's maximum pressures for those two rims are totally different. The XC MTB stuff is 63psi for a 2.0", 88psi for a 1.5". Their road rims are 138psi at 23mm.
Open pro looks quite a bit chunkier in profile, although some of that is because of the braking surface.
I didn’t realise my E1900s were classed as that good if I’m fair. It was the standard wheel option on my Bird.
Wondering if I should try and negotiate a wheel upgrade on the Cannondale at point of purchase - see if the shop will take the standard wheels from me as part payment towards something nicer that would push the weight of the bike nearer 8kgs.
Yeah the E1900s are about on par with Hope and other enduro wheels weight-wise, they're just a bit less refined and not as stiff or tough as the EX471 / hope wheels I replaced them with.
They go for £200-£250 separately IIRC, those 'dale wheels are more like £100 level, or less.
If they won't do a deal, look at the Cero AR24 Evo wheels for a cheap, much-lighter upgrade.
I doubt they would as they're not exactly expensive wheels and will be difficult to sell.
While we're on it, my last road bike was full carbon, Ritchey WCS finishing kit, Ultegra 6700 and RS81's and it came in at 7.25kg all in in a 55cm, considerably lighter than my carbon 29er HT with Fox 32SC, SLX / XT 11 speed mix at 10.4kg
I was going to make the point about a £3k 8kg road bike not being particularly great value if you're after light weight, but I think it's been made.
For the record my road bike was £950 and weighs 8.2kg.
My commuter was about the same so all in, and weighs 12.4kg, but it has discs, dynamo lights, a rack and mudguards, and is certainly not a road race bike even without the rack and guards!
My do it all HT would probably cost about £1k to build up, and is about 13kg with big tyres on, maybe 12.5 with something more ligthweight.
My full sus was £1k second hand, and probably weighs 14 or 15kg, I haven't weighed it. It seems to be "a reasonable weight for a 29er trail bike".
To my mind, the road bike is quite a lot lighter, even though some parts won't weigh much different. Some bits like the bars and stem are probably heavier. Rims and frames have to resist dents on either bike as others have said, plus most road rims will have to have some wear allowance for the brakes.
I don’t think those cero ar24 evo’s are disc compatible though are they?
Just for some bike weights see the below link on Cannondales 2017 bike range. Actual bikes being weighed weighed by bike rumour. Confirms my new bike at 8.67kgs - although I’m not sure what size frame they weighed. EDIT - they weighed size 56 frames which are a fair size. At 5’9 I’ve got a 54cm one coming and the saddle doesn’t need to be very high out of the frame.
One of the higher level supersix bikes is 5.8kg out of the box. I don’t think too many even higher end xc bikes are getting too close to that out the box.