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Discussion Starter · #1 ·
Down at the LBS I've run into a dilemma.

The wife seems to be pretty close to fitting two sizes of the same bike.

GF Marlin GS: 15.5 and 13 respectively...on the short one, her seatpost is jacked way up to allow for proper leg alignment...on the tall one, her legs feel/look good, but the standover and general feel seems a bit too large.

Since we are noobs, I can't really trust our opinions as far what fits best.

The next best thing I suppose is finding out if there are any reasons to beware of how high your seatpost is extended. Also, is there conventional wisdom that suggests which way to go when in between sizes?
 

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I see nothing wrong with the seatpost being jacked up high. As long as the smaller size does not feel cramped then I guess that would be the best fit. Smaller frames have shorter top tubes so that could make the 13" feel cramped. She should test ride as far as they will let her go. If they will allow her a good hour on the bike will give a much better sense of the fit.

There is a mark on the seatpost that tells you how high is to high. More of a min. insertion mark.
 

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From the limited amount that I know, it's better to be on a frame that's slightly to small and compensate with the seatpost, stem, handlebars etc that it is to be on a frame that's too large.

As for having the seatpost jacked way up, most seatposts have a line marked on them (I think about 3-4 inches from the bottom) that should never leave the seat tube; doing so compromises safety. As long as this line is still buried in the seat tube she'll be fine. If it's outside, you can also try getting a longer seat post.

On the smaller frame do her knees come anywhere near banging on the handlebars on sharp corners? Make sure there is enough clearance with the bars/knees so that even on corners sharper than you would think normal she can pedal unobstructed.

Edit: Sorry for any repitition! Maida7 beat me to it.
 

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Med got me thinking. Small frames also have an issue where the riders toe will hit the front wheel when turning and pedeling. It's called toe overlap. It's not a huge problem but can be very anoying for some. More prevalant on bikes with bigger wheels like road bikes and 29ers but also pops up on tiny womens frames.
 

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Discussion Starter · #5 ·
That's great...I didn't think of testing turning radious vs knee height in the cockpit, and 'toe overlap'.

Hopefully that will push us in a clear direction.

My main concern was the shop owner obviously over estimated the demand for the 2005 13" Marlin. He's got about 30 of them. He drastically lowered the price and seems to be pushing them pretty hard. He even trimmed the handlebars and shortened up the brake reaches to mirror the GS geometry on about half of 'em. Except for the seat I think there is no difference between the '13" Marlin GS' and the '13" Marlin' after his alterations.

Just to make sure...we are saying, if they both fit, smaller is more desirable.
 

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Discussion Starter · #7 ·
On the shop floor I would say +/-2" standover, probably on the short side of 2"...She's a towering 5'1" and change, with her shoes on.

This guy has had this shop for years and years...when we got there he held the handlebars and had her hop on. After a 2 second appraisal he declared the bike she was perched on, too large. He did the same to me, and suggested a larger ride.

I'm not saying I doubt his aptitude for eyeballing a riders fit, but...can any of you give me a hint about what he was looking at? How did he know without observing a ride?
 

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2" is not enuf standover. maybe on a road bike but never on a mtn bike. go with the smaller frame or shop a diferent brand that has a size that is in between and fits just right. Once again there is nothing wrong with showing alot of seat post.
 

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Maida7 said:
2" is not enuf standover. maybe on a road bike but never on a mtn bike.
I'd like to agree, but I'm far too short. If I insisted on more than 2" of standover I'd be riding BMX bikes. Sometimes you have to compromise. I convinced myself for years that I couldn't ride mountain bikes because they were all too big for my short legs. Now I'm the "wild man" on the group rides I go on, and crash the least. Go figure.

That said, seeing as your GF is only 5'1" I'd say go with the 13" bike. I ride a 15" at 5'6" and unless she has freakishly longs legs for her size I don't see how it would fit her. I also ride a 13" bike (which still leaves me with almost no standover) and while it occasionally feels cramped it's not too bad in general, and is a blast on the downhills.
 

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Maida7 said:
2" is not enuf standover. maybe on a road bike but never on a mtn bike. go with the smaller frame or shop a diferent brand that has a size that is in between and fits just right. Once again there is nothing wrong with showing alot of seat post.
I have about 2 inches on my GT hardtail. The size down would have been too cramped in the cockpit, and the standover has never given me any probs.

A 13 inch frame sounds tiny! There's probably only half an inch difference in length b/w the 15 and the 13 however, which is easily compensated for in stem length and seat adjustment. As long as she can get the seat high enough without running the post out past the minimum insertion line, the 13 inch should be OK if the length is in the ballpark.
 

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Sounds like you've already chosen. Try to get the shop to adjust the bike to fit her. She should have a flat back (not curved) Look at her knee relative to pedal. The small frame is probably good but the more important aspect is the fit including seat and bars.
 

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Discussion Starter · #14 ·
She went small.

So far, so good. I think that was the right choice.

Now we just need to get her stamina up and we can both get dirty...thanks for the help
 
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