Frustration with Frame Size

[brw0513]

Not that it is a big concern, but the eMTB that I had my eye on at the LBS has been sold. On a positive note, it gives me more time to do some research.

One of the reasons that I didn't jump on the Jam2 was a lingering question over frame size. A demo ride wasn't available on that particular bike - seems a common thing in Australia. Test bikes are available, but not in the model and frame size of real interest.

I'm 188cm, 61cm arm, 86cm leg.

On the Focus website, their sizing chart predicts a size L for my body dimensions. The LBS suggested XL for me without even asking my height. But they did only have XL in stock.

On the Specialized website, their sizing suggests a size L. But the salesman recommended XL, again without asking me to confirm height. I did ride the bike and felt ok. But it would have been great to also try an L to compare.

On the Merida website, their sizing suggests a size XL. But the salesman recommended L!

And on the Commencal website, I'm bang on the L/XL changeover.

Anyone else go through this dilemma?

I'm tending towards the L frame size given I think it will be a sportier ride.

Good advice appreciated.

Thanks.

 

[bluewater87]

I'm same height as you. my enduro and dh bikes are 488/490mm reach.
I test rode a large rail 7 and its 465/470mm reach was definitely too small to consider purchasing unfortunately.
The high seat tube length (500 mm) of the XL is a bit of a buzzkill

 

[Flatslide]

Yeah, I'm 6'2" 80kgs etc. My Trek and Rocky are XL frames. They can both be tricky in super tight switchbacks with their long front-ends, but it's really just a matter of adjusting ride style. The bonus is there's plenty of room to be comfy on a decent ride. I've found I prefer that slightly longer wheelbase on fast descents too, very stable. I'd add both of my bikes have a high seat tube, but I run my dropper 30mm up from lowest anyway, otherwise the seat is too low. Getting behind the bike is easy with the legs of a 6' plus person

 

[iXi]

Same height but shorter legs, long torso. On a giant large it was way too cramped, they couldn't get an XL in so that ruled that out. The merida large was spot on and felt so comfy but I didn't want the 500wh external battery. The norco only came in large and it's maybe a touch small but I've made it work for me, reach is 470. It's hard to get a good feel when most shops only carry medium and either a large or XL but never both.

 

[brw0513]

With little experience it's hard to know. But I suspect rider to bike fit would be just as important on a MTB (electric or otherwise) climbing and descending than the road bikes where there seems to be automatic acceptance of a detailed fit up for frame size before purchase.

I've even tried drawing up a number of bike geometries in CAD, but sometimes the published geometry figures don't seem to stand up to close scrutiny and are often incomplete.

Why don't the different manufacturers have an interactive smart phone app for frame geometry e.g. effective top tube length, reach, stack versus human anatomy to help select with frame sizing? The output could just be sporty, neutral or touring etc.

Maybe I should re-visit my local Specialized store and ask them to be more diagnostic. The do have one of those static jigs with the gazillion adjustments.

 

[cemoz]

Yep it sucks in Australia, I’m at the other end of the scale mostly need an XS frame can sometimes ride a S. All the shops in Perth only have M & L bikes to test.

 

[nickfrog]

There is no uniform sizing between brands so ignore L/XL etc... Simply focus on actual numbers and geo.

 

[GrandPaBrogan]

I'm not a fan of the current trend of going to the next size up. When I went to shop for eMTBs all my LBS could say is seeing as I used to ride old school Mediums, I really should get a Large. Problem is, for the type of riding I enjoy doing even the medium felt like a lumbering truck to me. I ride tight natural trails and hardly go to manicured MTB parks.

I stuck to my guns and went for a Small (which still had a longer wheel base than my old school acoustic Mediums). I'm pretty sure this may not be right for everyone, but after nearly a year of riding this was definitely the correct choice for me and what I enjoy doing.

Below is a video that pretty much explains why going for a modern S or an XL can be equally justifiable for the same rider - depending on the terrain. As he puts it in the end... “Mountain biking is fun… ride what you’ve got because it’s probably pretty great… geometry isn’t everything… being timed while climbing sucks!” Peace...

 

[04fuxake]

I'm the same height as you and I am dead on the cusp of L/XL in Giant frames. I went for the XL because it's reach was the same as my 21" Specialized. The Giant fits me really well although I did slap on a shorter stem/wider bars.

 

[GrandPaBrogan]

I'm the same height as you and I am dead on the cusp of L/XL in Giant frames. I went for the XL because it's reach was the same as my 21" Specialized. The Giant fits me really well although I did slap on a shorter stem/wider bars.

I did the opposite with my Small. I installed a longer stem (a 65mm Nukeproof Sam Hill) to get it just right.

 

[GrandPaBrogan]

When I bought my EEB, I went with my gut and went against the current sizing trend. I was a medium/large old school size, and I was being pressed to buy a modern large. Even the modern medium felt a tad too big for me. So I bought the small because it felt right - no regrets.

Just saw this video uploaded 18 March 2021. Interesting points they raised. So I took my RAD measurement just as they suggested. Surprise surprise, it was spot on.

Not saying these guys are right or wrong (can’t believe everything in the internet), all I’m saying is that their thought process and my gut feeling happens to be the same.

 

[GrandPaBrogan]

And while they’re at it, they’re also calling BS on ‘wider is better’ handlebar sizing trends too. They’re gonna be ruffling an awful lot of feathers...

 

[Konanige]

If you already have a bike you like the fit of try using 'geometry geeks' website to find similar sized bikes. Also if its a First mtb for you , super modern long low slack geometry may not suit you, its great for steep stuff but fully committing to loading the front wheel for grip can be unnerving if your new to the sport. If that front tyre goes your on the floor before you realise it.

 

[GrandPaBrogan]

If you already have a bike you like the fit of try using 'geometry geeks' website to find similar sized bikes. Also if its a First mtb for you , super modern long low slack geometry may not suit you, its great for steep stuff but fully committing to loading the front wheel for grip can be unnerving if your new to the sport. If that front tyre goes your on the floor before you realise it.

I’ve done BMX during in its early days and owned a couple of dirt motorbikes. Rode XC and AM bikes when they first came out until I gave up offroad cycling in 2006 (on and off over a 40 year period). I am aware of how and why everything has evolved the way it has. Most of which I enjoy and appreciate - benefiting from modern improvements. Some I can’t agree with, but like many things is a matter of personal preference.

Bought my first modern EEB in 2019, when I started cycling again. A small size as it turned out - which still has a longer wheelbase than all the various old school acoustic MTBikes in medium/large (18-19”) I’ve owned - including a 8” travel lFS DH rig. I’m a dinosaur with a different mindset when it comes to bike sizing... but not something I would impose on anyone. I was just surprised (if not amused) to see that there are still some people that are subscribing to the old school logic when it comes to bike sizing.