[Closed] How many reaches? (long/low/slack content)

Depends on if you have long arms or not.

My missus has the same length legs as me, but shorter body. We've basically settle on me liking a 460-470mm reach, and her a 430mm reach.

Bikes are fun. Numbers are good to obsess over on the internet when you get bored at work and need a poo.

75mm stem?  Party like it's 2003 eh!  😉

With the given figures, I'd say your reach is at least 18-20 months short...

Your current bike is not bringing in any where near enough revenue to the bike manufacturers, so you need to gain AT THE VERY LEAST 50mm on the front centre ASAP, lest your bank balance becomes too healthy.

Seriously though, on plucked from arse figures, I'd say 480-500ish mm of reach would see you right until the next big thing.

There’s no magic number (that’s just lies really, but it’s more than just reach). It’s what works for you.

Dirt jumping 400-420
DHing 450-475
Enduroing 475-500
STWorlding 500+

Ps. You owe me £150 for the bike fit data

You wanna try something about 500mm reach, perhaps a touch longer.

450mm of your XL bike minus half the 70mm stem (so you can run a 35mm long stem), plus 10mm or more for the hell of it.

Is there a compromise by going all out on reach in larger sizes?  Not many designs have bigger chainstay lengths.

I've entered a few enduros and I'm solidly middle order (vet class until next year when I'll be grand vet).  On trails I know, I'm fast(ish).  I fail to turn practice and sighting runs into speed on timed stages although I can go back to the venue and find that speed through repetition and confidence.

So I guess if I'm blaming the bike I'm looking for the magic combo that is going to make me feel confident soonest.

Is that what reach gives?  (in XL sizes, with proportionally shorter chainstays)

Or...

Do I need chainstays? If so, how many to go with my reaches?

two

typically anyway

One of my sons bikes is a Radon Slide, supposedly a few reaches short of an Enduro, brah.

Try telling him that it's 'too short' as he leaves you standing and launches into a fast set of sloppy Joe turns...

You have to find your own way with these things and it can be a struggle if you aren't Mr or Mrs average.At 5'7" I  have disproportionately long legs/short torso - I found something interesting that confirmed this to me this week-the Sitting Height Ratio-ie  (Sitting Height/Standing height)x100 = ? mines 49.4 ( I'm heading toward the longest legged peeps  with Aborigines @ 47.3 with the shortest legged  Guatamalan Men @ 54.6 ) the  average is 53.5. Eye opener indeed.

Today  I got to ride a bike that is mean't for people 6 foot plus(Stanton Switchback 18 Long  444 reach/619.5 stack),but because of its short chains stays -  415 mm ,higher BB ,and higher Stack compared to   my current bike (Stanton Slackline 16.5) it felt good....despite its Reach being longer than I currently have or could  cope  with without the other changes.

Have you tried the new reach assessment tool? The Reach Around has been a revelation for me, just google it.

Do I need chainstays? If so, how many to go with my reaches?

My preference would be for at least 440 chainstays - and I prefer 450 (that's with 460 reaches).

I do love them chainstays though, mmm-mmmm!

So have I got this right?

If the head tube is shorter the reach will be overstated (more headset spacers needed)

If the BB drop is greater  the reach will be understated (fewer headset spacers needed)

e.g.
Nukeproof Mega 275 Large vs Devinci Spartan large (Lo setting)

1226 WB vs 1222 WB

435 CS vs 430 CS

115 HT vs 125 HT

Both 65 degree HA

Both 170mm fork 27.5 wheels

BB drop 10 vs 16 (?)

600 stack vs 625 stack

470 reach (overstated) vs 465 reach (understated)

I'd expect the Spartan to feel longer in reach by the time I've adjusted my contact points on both.

Reach is a standardized  horizontal  measurement of the particular frame so it is what it is.

Reach is a standardized  horizontal  measurement of the particular frame so it is what it is.

Sort of. It's affected by stack. If you have two bikes with the same reach, and one has a lower stack, to achieve the same stack height you'll need to add spacers under the stem. This combined with a slack head angle reduces the effective reach, and can have a considerable affect.

The Giant Reign is a perfect example of this, where the head tube is tiny, so stack is very low, and riders end up with a lot of spacers, which shorten the bike.

You can combat this by not running spacers, but running high rise bars, and turning the sweep up, not back.

But it's a compromise.

Reach, stack and ETT are needed to really understand how a bike will fit.

Mega vs Spartan:

https://geometrygeeks.bike/compare/nukeproof-mega-275-2018-large-18,devinci-spartan-2018-l-lo/

Also...

Sort of. It’s affected by stack. If you have two bikes with the same reach, and one has a lower stack, to achieve the same stack height you’ll need to add spacers under the stem. This combined with a slack head angle reduces the effective reach, and can have a considerable affect.

This. Every 10mm spacer shortens reach by about 4mm, depending on head angle. (reference: trigonometry)

You can combat this by not running spacers, but running high rise bars, and turning the sweep up, not back.

If you're moving your hand position forwards you have the choice of high rise bars and rolling the bars vs. longer stem, spacers and lower rise bars.  The difference between those two is cosmetic, right?  Maybe a bit of wrist angle depending on the bar? Not the same as having a more reachy frame?

“You can combat this by not running spacers, but running high rise bars, and turning the sweep up, not back.”

You cant cheat geometry like this - the high rise bars can only gain reach by adding effective stem length.

I'm a spidery 6'2" with long arms and legs and sat on an XL Whyte 901 the other day. It has a reach of 501 mm and it was way, way too big

You can combat this by not running spacers, but running high rise bars, and turning the sweep up, not back.

But it’s a compromise.

Reach, stack and ETT are needed to really understand how a bike will fit.

And end up with an uncomfortable bar position, no ta.

I put together a spread sheet which sets the bar height from the BB, means I can get an idea of what size I should be demoing. Its reasonably accurate and also gives me a check of seatpost insertion if looking to size up. Having demoed a few bikes (and of two sizes in some instances) its been validated a bit.

Some manufacturers have a fair gap between M/L/XL and could almost do with splitting the large IMO. Road bikes are in 2cm increments, why can't MTB have that?

Its so subjective and opinions can be based heavilly on what your used to rather than what could be better for you with some time to adjust.

I’ve probably owned 15 bikes all large or xl. I’m 6ft and half an inch with a 33 inseem and 6ft 2 wing span. The only 2 bikes that fit me properly knowing what i know now are my lst 2..... a large whyte g-160 and a large mondraker foxy xr. Both in the 490-500 reach range with 35mm stems to pull a little of that back in.

I even built myself a lovely kingdom vendetta ti x2 which will be in the for sale section shortly! with a 460 reach it should have  been “perfect” sizing wise for me going by convention. Instant bad back and cramped feeling that 5 or more hours of riding diddn’t help, shame - amazing bike.

I’m definately a long convert, not sure about being overly slack, 66 degree-ish is fine. Steep seat tubes are nice and pretty integral to the geo also as are chainstays that arent too short, there needs to be a balance (mondraker set in in 435 mode, not 425)

Interesting about the whyte. Same height here maybe half inch taller and the whyte one of few bike that actually fit well

Bike sizing shouldn't be subjective-it 'should' be science.We don't all go out to buy shoes and think hmmmmm those shoes they have  over there are nicer but are the wrong size but I could just by some big thick insoles and stuff tissue in the toes-yeah that would work .

Bike sizing should start with us and knowing the dimensions and balance of our own bodies as we are all proportionately different.

Any bike that allows you to easily stand in your bodies own naturally strong balanced  stable comfortable  neutral attacking position-is the correct fitting bike.

misses the obvious point that you can adjust a bike to fir you which you can't often do with shoes though.

Sure you can and should fine tune fit on a bike and that kind of is my point-you shouldn't have to  compensate/tune too far  away from any given  frame design if it had the  off the peg sweetspot of fit for you in the first place.

sweet spot for what though?

I would have thought an XC bike will have different geometry to a DH bike or a road bike, or a jump bike... they're all going to be different sizes but "fit" will be determined by purpose/fun/time spent on it...no?

I'd say its not simple. Something else to consider is definitely seat tube angle. Im 5ft 11, and recently demoed a bike with 520mm reach. I loved it, and plan to buy one, the seat tube is 77 degrees though, if it was slacker it would be too big. When i ride more traditionally sized bikes they just feel too small. Ive allways liked bigger bikes though,  and know other people who prefer small bikes. Id say try as many as you can.

Bike sizing shouldn’t be subjective-it ‘should’ be <span class="skimlinks-unlinked">science.</span>

It's not though - it's highly subjective.  If you own multiple bikes, you get on one, get used to it, then the other bike feels really weird, but then you get used to that and the first one feels weird.

A bike that felt utterly perfect in 2008 felt dreadful when I got it out again last year.  Bikes evolve because of our tastes but also importantly vice versa.

The sweetspot for you Nick-your gonna be the same proportionately shaped human no matter what style/genre type of bike you transpose yourself onto to.

This thread is about sizing of enduro style bikes designed for the  purpose of climbing to descend  - so  achieving the best neutral standing attack position would and maybe should be priority with buying these .

"Road bikes are in 2cm increments, why can’t MTB have that?"

The goal with road bike geometry is a mix of aero and pedalling efficiency, vs comfort, whilst handling is far lower down the priority list. Much more of MTB geometry is about handling. So with a road bike you can add stem length to help fit, whilst with a modern MTB you've only got 30mm of stem to play with at most.

If you want MTBs to fit riders from 5' to 6'3 (98th percentile for US men and women) that's a 38cm difference in height and as torso length is about half of that that's a 19cm difference in reach. If you expect the tallest rider to run a 60mm stem and the shortest a 30mm stem, then you need a difference of 160mm reach between XS and XL.

So with five sizes, XS, S, M, L, XL the reach measurements should be something like 370, 402, 434, 466, 498, 530.

If you have long legs for your height, then you'll need a shorter reach bike than a rider who is shorter but has a longer torso. I don't believe arm length really comes into, except at one extreme where a short armed rider will need  shorter reach so they can get their weight back.

Cheifgrooveguru is on the money for me here.

Sizing is something I'm sensitive too,being 5'7" with longer legs shorter torso for me bike reach is  governed by my relationship with the rear axle and whether I can get to it when I need or want to.Take that reach too far away from me and the front end feel more and more like it's  strapped down near to the ground.'For me' I've come to the conclusion that on the whole I need a relatively high stack,low reach and if possible shorter chainstay bike ."if' the bike has a very short chainstay /higher bottom bracket like the 415mm of the  largest longest  sized Stanton Switchback I tried at the weekend then I can cope surprisingly  well with a longer reach.

I put together a spread sheet which sets the bar height from the BB, means I can get an idea of what size I should be demoing

I think this.

I've recalculated frame reach for one consistent stack height (as though I was adding spacers to get the height up on the low stack frames).  Other requirements: 1) short seat tube (for a big dropper); 2) longerish chainstays

As I'm coming from a very short bike setup I think I'll get adequate "ooh, I've got more reach" from the 480mm end of the nominal 480-500 "Enduro" reach range.  That's still 45 more than I've got at the moment (on my normalised calculation) which also gets close to the "halve my stem length and add 10" formula.

- Whyte G-170 (L) is on the list.  Now they do the 29er that also works but both are a little weird on BB height.  29er has longer chainstays (435).

- Capra (XL) in either wheel size.  I'm annoyed it so perfectly fits the bill.

- RAAW Madonna (L) is the joker entry in the list that meets all the criteria.

- Bird AM9 gets in the running. L is a bit longer than any of the others mentioned so far.  ML is shorter.

If I'm going to allow 150mm travel 29ers, the Whyte S-150 (L) is obvious.

If I relax the reach requirement a little further:

- Commencal Meta 29er (L)

- Orange Stage 6 (L)

A little bit further still:

- the new Commencal Clash

Commencal are a bit weird in that their XL are two sizes bigger than their size L; same for Nukeproof whose size L is too short to consider.

Nomad (XL) is at the upper limit of seat tube length and has the shortest chainstays I'd consider.   Same could be said for the Radon Swoop (size 22 XL) and Devinci Spartan (XL).