MTB sizing advice/debate

[Bru1991]

Hello Everyone

 

I seek some advice regarding frame sizing and modifications to set-up.

 

I am 1,78m weight 86kg's wide shoulders , fairly proportionate legs, arms etc.Not a beginner.Previous bike BMC Fourstroke XT Medium.

 

I was advised by a sales rep at a store to go with a Medium frame Scott Spark RC Team.The purchase of the bike includes a "professional" bike fit which took about 15 min ( WARNING SIGNS ).Didn't think much of it because hey , I am a experience mountainbiker.

So got home after purchase and immediately adjusted the saddle height which was very low.And never looked back.This was 9 months ago and I have only done about 3500km's since then ( Being a new father ).

 

The bike is great, but I have a very "front-wheel-heavy" type of ride feel,I also struggle to get the front wheel over things.But not that much that I can't do it.The bike also feels tight in the crank BB section.This made me investigate the suspicion of maybe having a slightly to small frame.

 

Scott's sizing guide on the website shows that I'm just just just just within the medium frame sizing.You could say I am right between Medium & Large

 

I think height of saddle and front/aft position of the saddle is my biggest issues.As increasing the reach space by sliding the saddle back works......but then my knee aft position gets effected by the further back position and I can feel it effects my power output.

 

So what I want help with is: Should I do the whole wider handlebars, longer stem, pro set-up scenario. Like would this be fixable, or should I shut up and save up and ride the Scott until I A) become so fit that the bike works LOL or B) can afford something else ( read: new father, probably only going to happen in like 10 years )

 

I am attaching pictures for reference, I know this doesn't show actual force being put through the pedals. But maybe you get an Idea.

 

Any advise would be much appreciated 

 

Sidenote Should the sales rep have spotted the crampness.

 

[greg_sa]

Yep, I agree - bike looks too small.

 

I'm 1.80m, and when I was looking for my 1st bike (new to the sport) I was told by a few bike shops that I could go medium or large (was looking at Giant Anthems).

 

I am very glad I went for a large! I think if in doubt (on the boundary), always choose the larger frame.

[Bru1991]

Yep, I agree - bike looks too small.

 

I'm 1.80m, and when I was looking for my 1st bike (new to the sport) I was told by a few bike shops that I could go medium or large (was looking at Giant Anthems).

 

I am very glad I went for a large! I think if in doubt (on the boundary), always choose the larger frame.

Now knowing this, I would to.Its unfortunately a expensive mistake.

[DieselnDust]

Looks fine but on the small side. The handlebars look very low. Is the stem flipped upside down to negative rise?

 

The reach looks OK to. Shorter than I prefer my reach but I'm not you.

if you want to unweight the front a bit try flipping the stem to positive rise to raise the bars and then move the saddle backward by 5mm to keep the reach the same.

If it still feels short then try a longer stem.

what are the current measurements of bar to saddle and saddle height etc?

[BMXER]

I am the same height and often between frame sizes. I ride a bmc medium and live the bike.

 

That said the bmc four in a medium is on the larger side of frame builds. This may have affected your decision.

 

Try a 100mm stem and loose the negative.

[MudLark]

I am exactly the same height as you but a little bit lighter. In the Trek range, I fit on the cusp between large and extra-large. Just looking at the photograph, I think you have been sold a bike that is really much too small for you.

[Odinson]

I'm a hair shorter than you and I'll probably never buy a traditional medium framed bike again. I think you could've even gotten away with an XL, seeing as you're running a fixed saddle post. 

 

I've been riding a large framed enduro bike with 473mm reach and can't see myself ever riding anything under 465mm. 

 

One of the few bike brands that seem to be getting reach on XC frames correct is NS, with their new Synonym bike - 475mm in medium and 500mm in large. 

 

[Longbarn Killer]

No wonder the front wheel feels heavy, look at the stem position.

 

The pros might be able to get away with a position like that, but hey, we are normal people.

 

I'm the same height and have a medium Scott hardtail, but ride a large road bike.

 

 I would flip the stem and see how it feels. You have been riding like that for some time now, so you going to feel pretty weird when you do flip it. Give it a few rides to see how you feel. If, after a few rides, you can't get used to, then flip it back.

[slickjay007]

A wrong size bike that is too small can be easy to make fit if it only requires small changes but past that you may need different parts such as a stems or seat post. 

 

Longer Seat Post

The first thing that you should adjust on the bike is the height of the saddle. Seat posts typically have a fairly long length so can be extended quite far. On all seat posts, at least if it hasn’t worn off, there is a maximum extension mark. Never position the post past this point as there is not enough post in the frame to adequately support the weight. If you do, the frame can actually bend and break quite easily. The solution to raising the seat further is to get a longer seat post which can be found relatively easily at your well stocked local bike shop or online. A 350mm length post is about as long as you can easily find. Just make sure you get the right size diameter post as most bikes have different sizes.

 

Increased Saddle Set-Back

Having too small of a bike places you too far forward on the bike. Sliding your saddle back can help solve this. The first way to do this is to loosen the bolts on the rails of the saddle and slide it back as needed. If you find you can’t slide it back far enough, you can get a seat post that has increased set-back. Standard typically ranges from 10mm to 20mm. You can find however 30+mm setbacks but you’ll have to shop around. And if you find a post with the right set back but the diameter is too small you can use pre-made shims to make it fit properly.

 

Longer Stem

The next area of the bike that is probably going to be an issue is how close the handle bars are to your body. The solution to this is a longer stem which will push the bars further out in front of you. Depending upon how long the stem is now, you can get a stem around 140mm to 150mm in length. The thing to watch out for here however is with an increased stem length, the handling of the bike decreases because of how far the bars are from the pivot point, the steerer tube.

 

Raising the Bars

The last thing that you will probably have to do on a slightly small bike is to raise the bars. You can do this in two ways. The first is to make sure that the stem is placed at the very top of the steerer tube with no spacers above it. The second is to get a stem with a high angle which will raise your bars. Zero to seven degrees or so is typically average but you can find stems with angles above fifteen degrees.

[DieselnDust]

Hello Everyone

 

I seek some advice regarding frame sizing and modifications to set-up.

 

I am 1,78m weight 86kg's wide shoulders , fairly proportionate legs, arms etc.Not a beginner.Previous bike BMC Fourstroke XT Medium.

 

I was advised by a sales rep at a store to go with a Medium frame Scott Spark RC Team.The purchase of the bike includes a "professional" bike fit which took about 15 min ( WARNING SIGNS ).Didn't think much of it because hey , I am a experience mountainbiker.

So got home after purchase and immediately adjusted the saddle height which was very low.And never looked back.This was 9 months ago and I have only done about 3500km's since then ( Being a new father ).

 

The bike is great, but I have a very "front-wheel-heavy" type of ride feel,I also struggle to get the front wheel over things.But not that much that I can't do it.The bike also feels tight in the crank BB section.This made me investigate the suspicion of maybe having a slightly to small frame.

 

Scott's sizing guide on the website shows that I'm just just just just within the medium frame sizing.You could say I am right between Medium & Large

 

I think height of saddle and front/aft position of the saddle is my biggest issues.As increasing the reach space by sliding the saddle back works......but then my knee aft position gets effected by the further back position and I can feel it effects my power output.

 

So what I want help with is: Should I do the whole wider handlebars, longer stem, pro set-up scenario. Like would this be fixable, or should I shut up and save up and ride the Scott until I A) become so fit that the bike works LOL or B) can afford something else ( read: new father, probably only going to happen in like 10 years )

 

I am attaching pictures for reference, I know this doesn't show actual force being put through the pedals. But maybe you get an Idea.

 

Any advise would be much appreciated 

 

Sidenote Should the sales rep have spotted the crampness.

 

 

 

Oh and another observation, it appears you have become used to a high ankle pedalling position hence when they set you up the saddle felt too low. If you really prefer that pedalling style then ok leave it as is but I tend to prefer a lower saddle with the saddle a little further back (to facilitate being able to eliminate the dead spot at the top of the pedal stroke) .

 

The now more common forward over the bb position is focused on being able to drive the pedals in the downstroke but the high saddle limits your leverage. this is also more beneficial on road bikes but theres an advantage on mtb for very steep climbs where you need to be more forward on the bike. But thats what long saddles are for.

 

I'd say there's quite a bit of work that can be done to get your position more optimised before tossing the bike away. Would you better off on a large? I doubt it.

[MudLark]

As an additional thought, your best option is really to take the bike and go see a really good bike fitter* and see whether they can sort you out properly. 

 

*There are lots of bike fitters out there but I have discovered to my cost that not all of them really know what they are doing. A lot of them "just work by the rules" and hope for the best kind of thing. Really good fitters are almost as much art as science. But even then, remember that a really good bike fitment is in a sense only the beginning. You will need to do finer adjustments yourself over time to get yourself to where you are really comfortable and can put down the power best in a way that works for you.

[RobertWhitehead]

Let's look at the facts: 

 

• Is the frame too small for you? - Possibly, there's some overlap on all the sizes and majority of the time the sales person will go for a smaller frame to give you more agility whilst on the trails as well as some better control.
• Do you look cramped on the bike? - Yes, but the frame may not be the sole contributor to this. 
• Does your knee extend over the ball of you foot when your pedal stroke reaches the 9-3 position? - Nope, it does not appear to be doing so no, you can take a plumline and measure it to confirm it
• One can now dissect it further and look at the angles and blah blah blah but I'm not going to go into sooo much detail

So my advice and by far the cheapest alternative for being a new dad: 

 

1. First things first: https://www.competitivecyclist.com/Store/catalog/fitCalculatorBike.jsp#type - this link will allow you to measure yourself and then spit out the dimensions for you to carry over onto the bike. I've had a few very good set-ups done before in the past and this link comes quite close. The major difference is the tolerance - the link gives you a wider range. 
2. Change the stem around from its current negative angle over to the positive, this will take the weight off your front wheel and also open up your shoulders, the end result will be a higher center of gravity as well as a more neutral position. This will take the weight off the front wheel.
3. Then I would test the bike after doing no. 1 & 2 then if the cockpit is still cramped and you still feel the bike is heavy and struggles to get over stuff then I will look into the bar width as a final ditched effort to resolve the issue. 

PS. If you do not know how to sort the stuff out mechanically feel free to pop over to my place and I will sort it out for you no worries 

 

Snip

[cadenceblur]

Damn. Looks like you have a lemon, some good suggestions to make some positive shifts though. I'm slightly taller at 1.87 and ride an XL for perspective and that works with a nice short stem on my bike brand. Good luck..

[Super Sywurm]

That bike is way to small.

 

I am 1.92 and weigh 78kg.  I am in the large / extra large category.  Most shops told me I should go XL, but I have been riding L for couple of years now and I am happy with that.  It's is also easier to sell a L.

[DieselnDust]

That bike is way to small.

 

I am 1.92 and weigh 78kg.  I am in the large / extra large category.  Most shops told me I should go XL, but I have been riding L for couple of years now and I am happy with that.  It's is also easier to sell a L.

 

 

he's 1.78m on medium (Scott recommended height range 1.68 -1.80m)

you 1.92m and on large (scott recommended height range 1.78 - 1.88)

 

You're riding a bike size below that recommended for your height and you love it but and the medium is way too small for Bru when he falls within the size range?????

I'm  not following your logic. Can you unpack your thinking a little more

[Super Sywurm]

he's 1.78m on medium (Scott recommended height range 1.68 -1.80m)

you 1.92m and on large (scott recommended height range 1.78 - 1.88)

 

You're riding a bike size below that recommended for your height and you love it but and the medium is way too small for Bru when he falls within the size range?????

I'm  not following your logic. Can you unpack your thinking a little more

Keep in mind, I don't ride a Scott.