FRAME SIZE SELECTOR

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FRAME SIZE SELECTOR

Postby mauriceandgrandad » 20 Jun 2011, 09:19

Wondering what size Frame is right for you? Check out the chart below and maybe it will help narrow down those decisions.

Rider Height /Frame Size /Top Tube Length

4'0" & under/ Micro-Mini /15"-15.5"
4'0"-4'6"/ Mini /15.5"-16.5"
4'4"-4'10"/ Junior /16"-17.5"
4'8"-5'4"/ Expert /17"-18.5"
5'2"-5'8" /Expert XL/ 18"-19"
5'6" - 5'10"/ Pro /18.5"-19.5"
5'10"-6'1"/ Pro XL /19"-21"
6' & over /Pro XXL/20.5" & over

This is a guide only. If possible borrow a bike the size you think you need and try it first before you spend any money.
Many clubs have loan bikes.
If it ain't broken, keep fixing it until it is!
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Re: FRAME SIZE SELECTOR

Postby rich_camm » 29 Jun 2011, 06:17

im 5' 7" and ride a proXL

where did you get this chart from?
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Re: FRAME SIZE SELECTOR

Postby mauriceandgrandad » 29 Jun 2011, 07:13

rich_camm wrote:im 5' 7" and ride a proXL

where did you get this chart from?


this chart is designed to assist newcomers to the sport, it is not a bible, but you have to start somewhere. Some people have long arms and short legs and vice versa. It does say try to borrow a bike the size you think you need before you buy.
You are an expert rider and that frame size obviously suits you as an individual, it doesn't make the chart wrong for general guidance.
If it ain't broken, keep fixing it until it is!
http://www.bournemouthbmx.co.uk/
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Re: FRAME SIZE SELECTOR

Postby rich_camm » 29 Jun 2011, 07:21

easy tiger

just wondered where you got your ideas from

i know british cycling do a chart like this too!
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Re: FRAME SIZE SELECTOR

Postby Jace » 11 Jul 2011, 01:30

Yea but your running 155 cranks too rich ;-)


Its all how you feel IMO, I'm runnin a 21" 125R like rich & I'm 5' 8" , sometimes it feels a bit long, others its perfect, i wouldnt change it for the world..
I have the solution for a problem that doesnt yet exist ......


.
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Re: FRAME SIZE SELECTOR

Postby mike-at-dialledbikes » 17 Aug 2011, 20:38

mauriceandgrandad wrote:Rider Height /Frame Size /Top Tube Length

4'0" & under/ Micro-Mini /15"-15.5"
4'0"-4'6"/ Mini /15.5"-16.5"
4'4"-4'10"/ Junior /16"-17.5"
4'8"-5'4"/ Expert /17"-18.5"
5'2"-5'8" /Expert XL/ 18"-19"
5'6" - 5'10"/ Pro /18.5"-19.5"
5'10"-6'1"/ Pro XL /19"-21"
6' & over /Pro XXL/20.5" & over


I know you didn't write the chart MG (so this isn't a diss), but I think the chart is incorrect.

e.g. most Pro size top tubes will be 20"+, Pro XL 21"+ and Pro XXL 21.75"+.

20.5" (as in the chart) would be ridiculously short for a Pro XXL frame. Those are like 1980's frame dimensions.
Last edited by mike-at-dialledbikes on 18 Aug 2011, 07:52, edited 1 time in total.
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Re: FRAME SIZE SELECTOR

Postby mauriceandgrandad » 18 Aug 2011, 07:07

Mike, If you have a more accurate chart, please let me know and I will change it.
If it ain't broken, keep fixing it until it is!
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Re: FRAME SIZE SELECTOR

Postby heliuscc » 15 Sep 2011, 07:43

A crupi mini top tube is 18" long, this whole chart is way out with respect to modern geometry. Thanks for trying though.
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Re: FRAME SIZE SELECTOR

Postby mauriceandgrandad » 15 Sep 2011, 08:13

heliuscc wrote:A crupi mini top tube is 18" long, this whole chart is way out with respect to modern geometry. Thanks for trying though.


As i said, it's a guide only.
A Kuwahara mini top tube is 17 1/4. Who is right?
Crupi calling an 18" frame a mini is pushing it a bit I think. Most of the little ones I see would need a zero reach stem to ride it. I've even seen kids on a 17" with the stem reversed so they could reach the bars.
BTW the chart is a average of several different ones out there, mostly American, as everyone seems to have a different view on the subject.

As I said, this is for information purposes, so if anyone can provide a more definitive chart. I will happily change it. :)
If it ain't broken, keep fixing it until it is!
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Re: FRAME SIZE SELECTOR

Postby grim2 » 15 Sep 2011, 21:34

Check out "stack and reach", a far better way of gauging a prospective bikes fit in relation to hands and feet, and more importantly perhaps,how it relates to a known quantity: the bike you ride at the moment or fit/dont fit.
Top tube length is near meaningless where half an inch can make a world of difference to the feel of a bike.Reach can quickly be gained and lost through different seat angles...

http://www.pinkbike.com/news/08ReachStackStandard.html

makes perfect sense, especially for a bike that is rarely used in a seated position....

I can only assume frame manufacturers dont think we are capable of using such info as it is very rarely given...
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Re: FRAME SIZE SELECTOR

Postby Smartihawk » 19 Feb 2012, 22:25

rich_camm wrote:easy tiger

just wondered where you got your ideas from

i know british cycling do a chart like this too!



Lmfao
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Re: FRAME SIZE SELECTOR

Postby Smartihawk » 19 Feb 2012, 22:44

grim2 wrote:Check out "stack and reach", a far better way of gauging a prospective bikes fit in relation to hands and feet, and more importantly perhaps,how it relates to a known quantity: the bike you ride at the moment or fit/dont fit.
Top tube length is near meaningless where half an inch can make a world of difference to the feel of a bike.Reach can quickly be gained and lost through different seat angles...

http://www.pinkbike.com/news/08ReachStackStandard.html

makes perfect sense, especially for a bike that is rarely used in a seated position....

I can only assume frame manufacturers dont think we are capable of using such info as it is very rarely given...


Here here!!!! Yeah, bike sizing is kinda whack imo. In MTB frames, they size bikes by how long the seat-tube is, like wtf?! It's like whatever the seat-tube does, the rest of the bike has to follow.... In MTB hardtails, I like low-slung frames, where the toptube angles right down steep to the seat-tube, but this can only take effect with a short seat-tube, which in effect only comes on a small frame, because the corelating small seat-tube comes with a shorter toptube length etc. The only way round this is to order a custom-built frame (something I am planning on doing very soon).

I think BMX is totally different from MTB frame sizing. BMX frame sizes are determined by the length of the toptube... And quite rightly so, because you're going to be standing up on the machine when racing, not sitting down. Hence the 'reach and stack' scenario. Both 'reach' and 'stack' measurements have been in existence in the bicycle geometery world since the invention of the wheel, but you never hear about them because it's always toptube length and seat-tube length etc.(go to any Bike CAD online program and draw your own frame, you can select the stack and the reach). 'Reach and Stack' are obviously directly corelated to toptube lengths and seat-tube lengths and their corresponding angles anyway, so it's just another way of determing a size of a bike. If you have two identical bike frames, one with a 20" TT, and the other one with a 20" TT, but the second one has it's seat-tube angled tweaked so the seat bends back a few degrees, the headtube angle will be slackened and dragged backwards, tilted backwards along with the seat-tube. But if you kept the headtube fixed, and tried to angle the seat-tube backwards a few degrees, you would HAVE TO make the toptube LONGER.....

So toptube lengths should really be issued with seat-tube angles in the same sentence imo. Hence why that 'reach and stack' measuring method makes much more sense, because the measurement is taken from where your feet are placed either side of the BB to where the headtube is, or where you grab the bars etc. Much better system.

But let us not forget the importance of the seat-tube. It is the heart of the bike frame. It's what gives a bicycle it's looks and character. It's the seat-tube that transforms a BMX into an MTB into a Trackbike; simply by changing the length and angle of it. Downtubes are the same on any bike, ditto toptubes, ditto rear stays. 74 degrees is the last stop for a seat-tube angle, before it starts to make the bike look ridiculous. Redline BMXS and similar, have 70 degree seat angles, which is sweet, nice and laid back.
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Re: FRAME SIZE SELECTOR

Postby DaveHull » 29 Mar 2012, 09:08

Strange my Son is 4ft 1" tall and rides a Mini Ripper with a top tube of 16" I think and no one has said it's to small for him !
Do you measure the top tube to were the headset starts or the center of the headset ?

Dave.
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Re: FRAME SIZE SELECTOR

Postby DaveHull » 21 Jun 2012, 20:57

Hot topic this :lol:
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Re: FRAME SIZE SELECTOR

Postby Spectre » 28 Sep 2012, 14:53

Im 6ft 1 and ride a supercross envy pro xl, 34" inner leg (very long!) and arms like a guerilla.. and i find that the xl is fine, i know people who are 5ft 11 and ride 22" toptube bike with 15" 75 back end, stupid really.. no need for such big bikes, anything over 21.5" top tube is too big unless you like 6ft 5 IMO, your just making riding hard work for yourselves, and around 15" is as big as you will want to go rear end wise if you want to manual through triple's or more, those FTB frames look like they are pretty good for sizing, just my opinion,

John
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Re: FRAME SIZE SELECTOR

Postby ChrisCarter » 24 Oct 2012, 08:22

This is the bike size guide from Danscomp.
Might be useful.
Attachments
BMX Bike Sizes.jpg
Team Race Day Video - We've Got You Covered.
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Re: FRAME SIZE SELECTOR

Postby rich_camm » 24 Oct 2012, 12:04

its way too vague
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Re: FRAME SIZE SELECTOR

Postby RINTINTIN » 28 Dec 2012, 13:59

I use the redline size chart....for kids just to give an idea roughly.

I find anyone riding something in the pro to pro xxl range, it's entirely down to preference, I've known people to ride XXXL & they're less than 6 ft - idiots. But like I said, personal preference, I ride a 21.25 & I'm about 5 ft 6...
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Re: FRAME SIZE SELECTOR

Postby LeeroySilk » 23 Dec 2013, 23:36

I've always thought there should be a measurement from the centre of the BB shell to the centre point at the top of the head tube. This being the two points where we mount the frame via cranks and stem / bars.
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Re: FRAME SIZE SELECTOR

Postby maxpenny40 » 12 Aug 2015, 10:12

LeeroySilk wrote:I've always thought there should be a measurement from the centre of the BB shell to the centre point at the top of the head tube. This being the two points where we mount the frame via cranks and stem / bars.


http://www.bmxnews.com/2015/07/reader-l ... ider-area/
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