How to determine your ideal MTB frame size

Waesfjord

Hi all,

I'm just starting a new thread to simply find advice for mountain bike frame sizing. I seem to get mixed info from shop people, unsure if they are just trying to sell a particular size or frame (yes I am cynical )

So the story is (for a Felt frame) if I'm on a 19.5" frame, I have no more than 2" clearance on crossbar, when feet on floor, however the reach to handlebars is a little far (elbows quite straight), when cycling around.
If on the 17.5" frame, obviously the crossbar clearance is much greater, however bike reach maybe a bit small, the shop people said it looked a little cramped and recommended a size up.

The bike frame reach can possibly be changed by the spacer length on handlebar to either increase (on smaller frame) or decrease (on larger frame), however the crossbar clearance cannot be changed, so unsure how to proceed.

I'm only a newbie to MTB, to be used mainly for offroad, and need to purchase a bike on the bike to work scheme this week, so little time for extensive trials runs besides a spin around a car park , so really looking for some practical advice.

what would people suggest (go for smaller frame and increase reach, as required or go for larger frame and reduce the reach and accept the <=2" clearance).

Cheers!

easygoing39

If buying a Felt I'd go to Eurocycles on the Longmile Road and speak to a salesman called Richie Byrne.He knows his stuff and is well known in the Irish mountain biking scene.You will get no bullsh*t,only good advice.
And I'd get the smaller frame with a longer stem.

el Bastardo

Choose whatever you're comfortable with (after a test ride). If it doesn't feel right, you'll know. When I bought my bike (from a reputable shop in the states) I was told that 4" top tube clearance was recommended. I still have the bike, ten years on, and love it enough to spend more on it than it's really worth.

Enduro

easygoing39 wrote: »

If buying a Felt I'd go to Eurocycles on the Longmile Road and speak to a salesman called Richie Byrne.He knows his stuff and is well known in the Irish mountain biking scene.You will get no bullsh*t,only good advice.
And I'd get the smaller frame with a longer stem.

+1... Richie is da man when it comes to MTBing.

And definitely err on the small side for a MTB.

Waesfjord

cheers guys - thanks for the info - pretty much as I was thinking anyway!

new2biking

I went for a felt Q series as I'm quite tall and the cross bar was slightly longer than other manufacturers on their 21.5" MTBs.

+1 for Richie in Eurocycles:)

Lawdie

another

new2biking wrote: »

+1 for Richie in Eurocycles:)

ravendude

Ditto for calling in to Richie Byrne, aka the godfather of Irish mountainbiking
He'll set you right for sure.

But generally, I would say the following:

• In general, if you really can't make up your mind, err on the side of the smaller frame. You're erring on the side of lighter and a bit more nimble. Its easier to "make" a slightly smaller bike work with a longer stem, and pushing the seat back on the seatpost. ie. Its easier to make a frame thats a bit too small bigger with components, than it is to make a big frame feel smaller

• Most manufacturers have a sizing chart. Felt have one here, but it seems not to be as detailed as I would like. http://www.feltbicycles.com/USA/2011/Inside-Felt/Support/Bike-Sizing.aspx . Click on your height on the left...
• You should be able to find the geometry measurements for the bike. The important one is "standover height". In general, if you measure your leg inseam (inside of your leg) you should have about an inch of clearance over this measurement.
• Try it if you can at all!!
• With some manufacturers, you can simply be in between sizing. In such a case, the reality is neither frame really feels bang on, and you may be better off going with another manufacturer frame that "sits in between" that sizing.

I'd have to say, its well worth getting a hold of someone experienced (like Richie Byrne as others have suggested), and can try the bike in a shop, or via someone you know.

Waesfjord

thanks for the info. That's a new sizing chart for me, as haven;t come across it before. I'm just shy of 5' 10".

Size guide has 5' 9" as 15.5 or 17.5" frame
Size guide has 5' 10" as 17.5 or 19.5" frame

I'm going to get a 17.5" frame (2009 FElt Q920), as although I have ~1" clearance or a little more on the 19.5" frame, the reach is a little bit bigger, prefer the more compact 17.5".

thanks for the help folks.

now I'm trying to sort out which pedals would be best to buy, may get one the the pedals that is SPD, however also allows casual footwear for spinning down to the shop etc.