Bike fit question??

Bike fit is...

important, but is also highly subjective to the riders preferences as well. It's also subject to the type of riding being done. For an off road bike and your size a 21" frame would be a bit on the large size, I'm 6' 5" and ride a 21 and it fits quite well out of the box. With a few tweeks it fits perfectly. So without seeing you on the bike and seeing how it's set up I'd have to say that the 21 is too big. It also depends quite a bit on the specific bike and the geometry of the frame, as well as the designed "purpose" of the bike. A cross country trail bike will have a different geometry than a cross country race bike and thus will fit differently. Also of importance is how you ride. If your do mainly road, rail trails and bike paths the 21 will work. If you are into serious off road that 21" will hold you back due to it's size and the frame geometry (measurements). A larger frame handles slower, has less clearance over the toptube, and is harder for you to move around on (body english). The cramped feeling you get on a 19" can be compensated for by installing a longer stem to move the bar out further, and /or adjusting the seat to the rear a bit, or even the use of a setback seat post. And that's just the tip of the iceberg when it comes to bike fit.

The key to proper bike fit is finding a good bike shop that understands the importace of fit. One that will take into consideration your body proportions, how you ride, where you ride, your personal preferences, and then work with you to fit you to the proper size frame. It's well worth it. Personally I've been riding for so long that I can sit on a bike and tell whether or not it will work for me and what changes I'll have to make to get it right for my riding style and preferences. If you aren't to that point then a professional fit isn't a bad idea.

Anyway, from your description the 21 is likely too big for you. But really hard to say without knowing allot more imformation. In the end though it's your choice.

Good Dirt

Patrick O said:

So could any one explane? Say I was going to buy a Specialized Rockhopper for instance for XC. What are the points should I be looking for, for a proper fit? Our local bike shop will let you ride the bike on the road in front of the shop.

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First, I'd like to congratulate you on getting on a 21" frame, much less riding it. That's quite a feat for someone your height, indeed. I'm right around 5'7"-5'8" and I ride a 15" frame. I can't even get on my boyfriend's 19" Stumpy.

Second, did your shop help you fit the bikes? If so, I'd say that they either didn't know what they were doing or else they just saw an opportunity to get rid of some stock and took it. Either way, that's pretty crappy. Maybe it's time to find a new shop that's not going to try to sell you the wrong thing just to make a sale...like a $2500 Stumpjumper for a beginner...

But I digress. To answer your questions...IMO, the very first, most basic things to look for are standover and reach. Standover is where you're standing over the bike (imagine that, eh?) and the distance from the top tube to your naughty bits is the standover height. Now, it's not a a hardfast rule, but if you can use your top tube as a seat, that's bad. Generally you want a few inches of clearance there - you be the judge of what distance makes you comfortable, but it should be enough that if you suddenly fell off your seat, you wouldn't do damage to the aforementioned naughty bits. Reach is how far you have to reach to grab the handlebars while you're sitting on the saddle. I know, I'm Captain Obvious today, but it's important because different people have different length arms and different ideas on what is comfortable. Some folks like to feel stretched out - almost like on a road bike. Some like to be sitting more upright. Again, that's personal preference, but if you're flat parallel with your top tube, probably not a good thing.

Of course, there's a bunch of other things that you should think about like leg extension, and control while riding. A lot of things can be tweaked and changed by swapping parts or making small adjustments. What you need to focus on is comfort, comfort, comfort. If you don't like the way the bike handles, don't get it. If you don't like the way it feels, try a different size. If you still don't like it, try a different bike. Bike's aren't all the same, and You might like a Trek 4300 better than a Rockhopper while your son might prefer a Cannondale F5 to a Trek 4300. It's all personal preference, and it doesn't sound like your shop took that into consideration.

Glad you've found mountain biking. Hope you become as obsessed as the rest of us. It's a good feeling. Good luck, and have fun.

Good advise DDD!

5'10" here with a 29" inseam! One of the long torso people. Minimal trail experience, mostly fire road and slab.
I've ridden over the years:
17" GT Tequesta- thought it felt a tad too small but the LBS said it would be stronger and fit better than the 19"-Purchased/Sized by LBS:
19" Trek 4900- thought it was way too big- but the color was cool- Purchased at LBS but I let color utlimately decide the size I bought
18" DB Response- feels pretty good, mostly easy dirt roads. Not really pushed it yet but happy with the fit. Purchased/Sized by LBS
17" Nashbar 29er SS- waiting for it to arrive- dimensions are only slightly smaller than the DB but promising for a SS. Sized by me based on previous experience.
You should be able to find specs for the frame your looking at but in my limited experience, here's what I've found;
Mediums are typically 17-18"
Large 18.5-19.5"
XL 20-21"

All bikes are/were stock.

Swthrtsuzy said:

First, I'd like to congratulate you on getting on a 21" frame, much less riding it. That's quite a feat for someone your height, indeed. I'm right around 5'7"-5'8" and I ride a 15" frame. I can't even get on my boyfriend's 19" Stumpy.

Second, did your shop help you fit the bikes? If so, I'd say that they either didn't know what they were doing or else they just saw an opportunity to get rid of some stock and took it. Either way, that's pretty crappy. Maybe it's time to find a new shop that's not going to try to sell you the wrong thing just to make a sale...like a $2500 Stumpjumper for a beginner...

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The more that you all tell me the more I have come to realise we are all basically on the wrong size bikes and they were just looking rid of stock. That's life we all live and learn. But we are all still enjoying ourselves and our group is getting bigger as each week goes past another two joined us this evening and loved it. The bikes we have will not go to waste they will do for anyone wanting to have a go and will always suit someone.

As for the bar and my naughty bits, I have to stand on my tip toes in order not to do myself an injury:yikes: LoL and I just hope I do not slip off the pedals for my sons and daughter will probably laugh for weeks.

I found this shop on the Internet it is about 30 miles away from me. We are thinking of getting ourselves a few good proper sized bikes that will hopefully last us a few of years

http://www.chainreactioncycles.com/...3&CurrentPageIndex=0&SortExpression=PRICE_ASC

I have to say thank you very much for all your help and taking the time to answer my questions. You are a great group of lads and lassies