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Caught between mtb frame sizes.?


Thomo
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Hi,

Established that my build puts me between frame sizes on mtb.

Reach or top tube length is the concern, and as a novice mtb-er I'm uncertain as to what to do.

What do you mountain kings suggest:

1. smaller frame + longer stem (57cm TT + 120mm stem)

2. larger frame + shorter stem (59cm TT + 100mm stem)

 

Advice is appreciated.

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Rule of thumb is usually to get smaller frame.

But a 120mm is quite long...

 

What does the bike shop suggest?

If they are any good, they should have a proper fitting & set-up facility

 

Failing that, make an appointment with Jeroen Swart @ Sports Science Institute...

 

Or have a Savanna. It's dry, but you can drink it.

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MTB's are normally sized in inches, like 16",18" etc

 

I'd suggest going with the smaller size. You'll have more control over the bike.

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MTB's are normally sized in inches, like 16",18" etc

 

I'd suggest going with the smaller size. You'll have more control over the bike.

 

That suits me most times too. I measure up for a medium, but mostly end up on smalls when it comes to MTBs.

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100mm stem sounds fine, whereas 120mm stem is very long. You'll be sending telegraph signals between the bar and wheels before steering inputs will have an effect on your direction. Those measurements sounds a bit wonky, maybe go for a second fitment opinion somewhere else?

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100mm stem sounds fine, whereas 120mm stem is very long. You'll be sending telegraph signals between the bar and wheels before steering inputs will have an effect on your direction. Those measurements sounds a bit wonky, maybe go for a second fitment opinion somewhere else?

Surely it will be the opposite - much like getting wider handle bars - you'll be able to put that front wheel exactly where you want it, and your bike won't be too twitchy.

I'd go for the smaller frame with the longer stem.

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You are 100% correct looking at top tube length rather then seat tube length. But if one make does not give you the size you require, look at another brand.

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Thanks guys.!

As you can see from the responses thus far, this isn't an easy question to answer.

But I appreciate the feedback and opinions.

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Thanks guys.!

As you can see from the responses thus far, this isn't an easy question to answer.

But I appreciate the feedback and opinions.

 

 

I have been there. trying to make a small frame work with 120 mm, not good.

 

Go for 100 mm option. What is the height of your saddle from middle of BB to top of saddle?

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I have been there. trying to make a small frame work with 120 mm, not good.

 

Go for 100 mm option. What is the height of your saddle from middle of BB to top of saddle?

 

Saddle height is ± 70cm.

Had a chat with LBS who did bike fit for road bike ... suggested virtual top tube length of ± 58/59cm on MTB.?

This seems to be average current M size frames.

My current bike though is 17" (M) but only 56cm TT, so relatively small and hence the additional stem length.

Larger frame I've been looking at is 19" - 59cm TT ... but I'm now also concerned about the standard over height/clearance on the larger frame.

Maybe I should keep looking for something more suitable.

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It depends also on your type of riding. If you're into racing and speed, a smaller frame, I have been told, is better. Its more agile around the tracks.

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Saddle height is ± 70cm.

Had a chat with LBS who did bike fit for road bike ... suggested virtual top tube length of ± 58/59cm on MTB.?

This seems to be average current M size frames.

My current bike though is 17" (M) but only 56cm TT, so relatively small and hence the additional stem length.

Larger frame I've been looking at is 19" - 59cm TT ... but I'm now also concerned about the standard over height/clearance on the larger frame.

Maybe I should keep looking for something more suitable.

 

 

I am riding 18,9" Scote scale. The top tube is 59-60 cm (horisontal , important). My saddle height is 78 cm (prefer higher than norma0 saddle height). My measurement of inside leg is 85 cm.

 

I see you are based in CT. Welcome to contact me and test ride my bike to make sure.

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