Frame size - do the same rules apply for EMTB...Size up or size down?

[skyfree]

Just to throw another wrench in this, as more of a beginner (1 1/2 years on eMTB but with years on moto-x bikes), I can't tell much of a difference between my 2 bikes. I'm 5'10" with a 31" inseam. The Haibike is a Small frame 2017 AllMtn 8.0. The Giant is a Large Trance E+ 1. I bought the large frame rather than medium because it's a loaner and most of the people riding it are right around 6'0".

The only obvious difference is on steep climbs. The Haibike wants to lift the front end and I have to get WAY over it to prevent that. The Giant climbs anything without much fuss. The difference is 465 chainstay vs 470 on the Giant, which doesn't sound like much to me, but who knows.

The bigger guys riding the Haibike say the same thing. I understand you experts can tell the difference, but for less skilled folks maybe not. I don't manual (yet) and wheelies are usually unintentional, but both of these bikes handle the same terrain pretty much the same way when they are on the same trail together.

 

[Gary]

it won't be from the 5mm difference in stays but rather the shorter front end of the small.
higher bars or a slacker seat angle also makes the front lift more easily (seated) climbing.
beginners also tend to pull UP on bars instead of BACK when exerting pedalling force climbing.

smaller frames do require more body weight shift to remain in traction. but that's also what makes them more maneouverable under a skilled rider.

 

[33red]

2 winters ago i was having fun climbing on my fat. Came may my summer bike refused to climb allways popping up in my face. I switched to a longer saddle(the one that was still on my fat) and i was enjoying climbing again. So many factors count. I had the technique but i had a weak link. Saddle position, obviously rider position etc......My small 2017 haibike climbs everywhere.

 

[ninjichor]

So why on earth are you running around the Internet telling us there's an exact ratio of wheelbase to chainstay length as if its going to be the same preference for everyone?

Do you have a reading comprehension or critical reading deficiency? I've said why in that post. I've made it short enough that even someone with short attention span would potentially read it.

It's not a ratio between WB and CS. It's the ratio between weight on the rear wheel vs front. I said I think the sweet spot is 60% on the rear and 40% on the front. How you get to it is another thing altogether--if you prefer to be in some sort of superman position like in the pictures above to get that weight bias, then yea, you might be fine with a shorter front end. Since I don't like that position, I made it a point to talk about how to get weight bias ratio through the RC (rear center, AKA horizontal CS length) and FC (front center).

It's a concept that can be imagined like this: if you could put pegs on the bike, where exactly would you place them to make the bike handle the best? I see tuning potential placing them somewhere other than where the crank spindle is currently at.

Let em go, I don’t watch much Tv so I need the drama!

Never knew about this weight biased stuff but I just weighed my Kenevo and it’s 59.8/40.2
I think the bike is absolutely perfectly balanced for me.
I can’t manual to save my life but that’s just me cause I’m shit at it. I am learning to pop wheelies though.

Keep up the babble guys I love to learn!

Was that done while sitting in the saddle?

 

[cozzy]

Not so much size up/down. I check the geometry. I dont want a tall seat tube, that gets taller sizing up. I look at wheelbase, less that 1240mm ideally for me at 6' with a reach of upto 470 maybe? So this is generally a large for me.
It feels wrong to buy a bike with a wheelbase longer than my dh bike!
I havent ridden one of these superlong 500mm reach 1300+mm wheelbase bikes but they sound far too big, maybe I will try one some day to verify. Probably great for the ews, likely less great for tooling around most uk sites.

And as for the arguing yes, keep it to the stw (same ten w*ankers) site please

 

[Fivetones]

Isn't interesting how a potentially good pub conversation just doesn't quite work on a forum.

Needless to say, there's some interesting thoughts in this that are adding to my learning to apply next time I'm out.

 

[Gary]

I don't like that position

Even when riders way more skilled than you who actually ride dynamically shift their weight even furter over the rear at times?

M'kay

I think the sweet spot is 60% on the rear and 40% on the front.

Stick all the bikes you like on two sets of weight scales. It won't change the fact while actually riding a mountainbike weight bias front to rear is a constantly changing variable. Or that each individual rider will have their own set-up preferences.
There is no ONE sweet spot for EVERYONE.

if you could put pegs on the bike, where exactly would you place them to make the bike handle the best? I see tuning potential placing them somewhere other than where the crank spindle is currently at.

Have you thought of designing an off road bicycle with foot pegs and a motor?

Oh... wait MX bikes already exist.

 

[Fivetones]

Like many I pour over geometry specs. I decided after trying the bikes in question. I went smaller (so, M, Orange Surge - I'm around 176cm high) according to the sizing chart. The bike feels good to me but I'm perfectly willing to accept the more and more I ride that might change.

 

[33red]

The thing is my 34.5 inseems might be on a 5,11 body or a 6,7.
We have a newborn.
The accordeon bike.
The tall one would hate my bike and i would hate her/his bike.

 

[ninjichor]

Even when riders way more skilled than you who actually ride dynamically shift their weight even furter over the rear at times?

M'kay






Stick all the bikes you like on two sets of weight scales. It won't change the fact while actually riding a mountainbike weight bias front to rear is a constantly changing variable. Or that each individual rider will have their own set-up preferences.
There is no ONE sweet spot for EVERYONE.




Have you thought of designing an off road bicycle with foot pegs and a motor?

Oh... wait MX bikes already exist.

Okay, why are you quoting me to tell me this? Are you looking for acknowledgement? This demonstration of your observations has proven that you're not a complete dolt living under a rock in complete ignorance.

How about replying with your opinion on why any of that (your observations) is, F/T mechanic? I'm also a mechanic, in the aerospace and defense, and the chief often speaking with the higher ups, not only pilots and officers but also the engineers (who I love talking to), trusted to make the final calls with +100 million dollars and other peoples' lives/careers on the line on a daily basis. How much is your mastery/expertise/knowledge/etc. trusted to make decisions on?

Arrogance game aside, I'm simply proposing something that makes it clearer what bike size to get based on what info the makers provide. Did you buy that Mondraker in a smaller size? If not, why? Are you not interested in something that is an improvement over that and why it might be? Do you not want to try and figure it out yourself, to save time and money?

 

[Gary]

Don't waste your time here trying to convince me of the validity of your narrowminded idea of what's "correct". Give this guy a call and tell him his bike's weight bias must be all wrong because you don't like the look of his position and think he looks unsafe while managing to be one of the fastest smoothest DH mtb racers in the world right now.

Arrogance game aside, I'm simply proposing something that makes it clearer what bike size to get based on what info the makers provide.

but you aren't. You're simply pushing your own idea based on pretty much nothing more than your odd perecption of riders moving their centre of mass rearwards.

it got dull a while ago

 

[ninjichor]

No weight bias really to compensate for with body position in the first pic.

He had an arms extended butt buzzing position for 1 instant in that whole vid. Most of the time his foot-to-hip leg alignment was inline with the pull of gravity. Arms bent most of the time, using legs as suspension.

In this picture, I'd say he's a bit forward than I'd say is ideal, but still you're stronger with the legs in this position, to counter big impacts like this.

As a bonus to the forward position, there's less movement (position change) to go from pedaling, to absorbing bumps, to cornering. Getting behind the saddle a little to allow the bike come up is one way to do it; another way is to get off to the side of the bike, like with a scrub. Looked like the saddle hit his pant crotch towards the end of the vid.

Also, the Specialized Demo is 430mm CS for 1208mm WB in M. I'd normally suggest 1210 WB for 430mm CS, but since the Demo has such a long fork and 63.5mm HTA, the front end gets quite a bit shorter in use when the fork compresses, so it's the equivalent to a ~1195mm WB bike. Consider 420mm reach and it's no surprise that he's off the back a little. I think it's in a sweet spot *for him*; it would be risky for anyone taller to ride off the back on a larger sized demo, I don't doubt. I'm so confident in this that I'd love to tell racers that they would feel better with certain tweaks, after observing their natural style.

 

[Gary]

go ahead man... he has a championship to hold on to and World champs to win in the next few weeks

 

[ninjichor]

Also it's perfectly fine that you get "bored" of hearing what I say. I got bored of brands putting out bikes with CS that are too long for their WB for my liking. Giant and Trek being two of them.

I've already talked to Loic, and a number of other racers, such as Aaron Gwin and Brian Lopes. We're humans, we got stuff to learn from each other. If you sound excited and confident enough, they will take interest. They are always looking for an advantage and have a high desire to win. Not unusual to see their names registered for local races (whether they actually show up is another thing), and not uncommon to see them at the local bike park even during the racing season, in between races. This was Cali Feb '16, in short sleeves and shorts.

 

[Gary]

Yeah. WC riders are just guys who love riding bikes. like you and me and are all (mostly) tottally aproachable and willing to chat lines etc.

Out of interest have you ridden Fort William DH track?

The video above is Loic riding there. the reason I linked to was not to show him hanging miles off the back arms extended. No WC (or decent for that matter) rider does that. but simply to show he rides it with a fairly rearward bias. The Fort william track is fast and rough but predominantly flat. it's easy to get hooked up and pitched forwards in a number of sections (this doesn't show too well on screen). I've ridden well over 1000 runs there.

Loic has ridden with locals here too. As has Aaron.
quite a few WC/EWS riders live and train near here.
(same places I ride)

 

[ninjichor]

It's not rearward though. The bike is merely angled down, but he maintains his upright position. It only looks like it's rearward in relation to the saddle. Vast difference between that and the position the riders are in, on the Giant Reign E+ (except for that last one... last one looks like he could use a shorter reach, shorter stem, and/or narrower handlebars, to get back even more).

 

[Gary]

No it is slightly rearward.
as i said. A lot of that track is flat
I haven't seen anyone ride a Reign E+

 

[ninjichor]

Ok, I watched again and I can't deny some parts have him rearward.

Looks like he stayed rearward for this position and got bucked a little cause his arms were too straight and he stiffened his legs for a short upsloped rock.

Looks like he shifts weight back up for the corner though.

The crouched position looks like a squat position to me, rather than a rearward one. The first pic definitely shows something that isn't a squat position--more like the toilet hover position that I dislike.

 

[CjP]

I'm a F/T mech dude.
#PreKeyboardz

Have been on and off for 30yrs

Lol all good dude, I can tell the difference between those that know their shit and those that don’t.

The comment was just a bit of humour.

 

[CjP]

Was that done while sitting in the saddle?

No standing straight up on the pedals.

 

[ninjichor]

What size is that Kenovo, Christian? Hopefully not XL, cause if I can fit decently on one, I'd add it to my list.

If it is XL, can it at least take an angleset, or are the bearing cups integrated? Also, what's your weight range? Curious if it offsets the weight of the battery.

 

[CjP]

What size is that Kenovo, Christian? Hopefully not XL, cause if I can fit decently on one, I'd add it to my list.

If it is XL, can it at least take an angleset, or are the bearing cups integrated? Also, what's your weight range? Curious if it offsets the weight of the battery.

Medium Kenevo
With clothes on 77.5kgs
Bikes 25kgs
29er front

 

[Gary]

Ok, I watched again and I can't deny some parts have him rearward....

...The first pic definitely shows something that isn't a squat position--more like the toilet hover position that I dislike.

Dude. No one. Not even a fully cookie dough ice cream fuelled Rock Jesus can hold the position YOU like for the entirity of the Aanoch Mor DH track. It's relentless.

My entire point was that in order to ride a mountainbike well you need to be dynamic. Not stood safe in the one position a certain distance between the wheels or exactly in the centre of the bikes weight distribution.

WC DH racing is not really all that close the general mountainbiking most folk do but actually is somewhere where bike/rider stability matters. (especially now tracks have changed to look better on TV) Arseing around on Emtbs not so much and if someone wants a shorter bike than YOU deem ideal because they want to hang off the back manualling it and popping it off kickers all day long or a shorter front centre/reach to bunnyhop easier or drag bike length stays to climb stupidly steep stuff or a stupidly high BB because they don't want to stop pedalling into and over obsticles. It doesn't matter what YOU (or I) don't like seeing.

 

[ninjichor]

Have you not heard of the Universal Athletic Position?

The bike is what moves/pitches/rotates forward and back. The legs/hip should stay in-line with the pull of gravity, unless you're doing a technique momentarily, like a bunnyhop. You crouch and extend the arms to let the front of the bike drop down. You stand tall and let the bars come close to your hips as you let the bike come off a steep jump lip to let the bike fly upwards.

When you go off a drop at low speed, there's a difference between the technique of A) throwing your hips back B) pushing the bike forward. They look similar to untrained eyes, but B) should feel stronger.

For example, the following picture is still centered to me, due to the angle of the legs and hips according to the pull of gravity. I see this as him letting his bike's front drop down, not him getting rearward. The important factor(s) is not the look, but the balance of weight distribution between each wheel and maintaining a strong position.

 

[Gary]

not all drops are the same
not all landings are the same
there are way more than 2 ways to ride a drop

Do you honestly NEVER manual off a drop?

it's perfectly possible to manual off a drop (weight obvs over the rear) and alter position in the air to land perfectly centred. Are you honestly saying a rider who does this is not maintaining a strong position?

Why all the closed minded rulebound opinions about how we "should" ride?

 

[ninjichor]

It's not closed minded if the idea was sufficiently explored before being deemed poor in comparison.

Do you ride your emtb off drops? Every drop you've successfully done on a regular bike before? Every drop you've seen riders of similar experience level successfully do?

I do most drops up to 5', except the ones that have a sketchy approach that can't be done at speed. I don't manual off drops since it's too unreliable. I've seen enough fail videos, including Seth's sicknic table, where a manual failed and dived back down prematurely. My method of speed and/or pushing the bike forward works for me.

 

[Gary]

No. it's extremely closed minded.
you deeming something "poor" does not make it so.

Yes I ride my Emtbs off drops.
No. Not every drop I've ever ridden before. That would be impossible. I've ridden Emtbs for about 18months but I've been riding mtb and doing drops for 30 years, lived in different places, travelled and ridden drops in many many places.
Any drop I'd do on a 170mm enduro bike i'd do on my 170mm Emtb
I still ride regular bikes too (I actually prefer them to Emtbs).

What's your point?

 

[Gary]

Just seen your edit

I do most drops up to 5', except the ones that have a sketchy approach that can't be done at speed.

Yeah 5ft isn't personally what I'd call all that big. I'll happily do drops quite a bit higher than that on a 100mm hardtail so long as there's a decent landing and probably dropped about 3 or 4 times that height on old DH bikes when younger.(back when hucking drops was popular). Now older I'm not actually a huge fan of drops unless they're part of a DH track or a set up for a feature in a jump/drop bike park trail etc. I just don't really find drops all that enjoyable in the grand scheme of things my preference is for hitting jumps over drops. and I'd genuinely rather hit a couple of nice corners for the drop in elevation a drop takes up I'm riddled with old injuries so harsh landings are really not my thing anymore either and rarely hit anything big that doesn't have a decent downslope/runout

I don't manual off drops since it's too unreliable. I've seen enough fail videos, including Seth's sicknic table, where a manual failed and dived back down prematurely. My method of speed and/or pushing the bike forward works for me.

Because you didn't take the time to learn how to manual confidently?
Whereas other riders (me) will happily manual off the edge of most flat edge drops with a nice landing as they are confident in having the skill to dip the front in the air to match the landing whether that be riding a BMX, hardtail, Enduro/DH bike or Emtb. Forget what you might have seen on "fail videos" Manualling off drops isn't actually an unreliable option if you can confidently manual.
Do you see yet that there isn't always just one way to approach everything? It's not actually as cut and dried as you make out and choosing what you deem to be the safest approach isn't everyone's preference (or even what is safest). This is why there's no such thing as the "correct" length bike. or f/r centre ratio/weight balance for everyone.