LMX P2 : Freeride trials motorcycle frame development

the bikes overall wheelbase may not need to be longer..
but the swingarm will be longer w a large motor mounted there..
this will effect the bikes handling!
climbing, cornering, coming out of corners, etc..

crossbreak said:
mounting a large motor on the swingarm will increase unsprung weight..
Click to expand...
if the motor is close to the pivot, its influence is negligible. the wheelbase does not have to be longer either, thats just a design question.
Click to expand...
 
ok then lengthen the swingarm by 50%!..
how is handling affected???
it is affected, yes???
ok now down to 20% length increase..
handling is still affected just less so..
some bikes are designed w short wheel base, some long..
depends on intended use.. short chainstays handle quicker than long..
trial/freeride bike usually has short chainstay & wheelbase compared w say a downhill bike..


crossbreak said:
the motor doesn't move. it just turns a little bit. its weight stays the same as well. Why should a longer 20% swing arm influence cornering? now i'm keen
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just to clarify..
swingarm length and unsprung weight are separate but in this case related issues..
w regards to the bikes handling..

for the quickest handling chassis the swingarm should only be as long as is needed to accommodate the rear wheel!..
 
or the quickest handling chassis the swingarm should only be as long as is needed to accommodate the rear wheel
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yes, ok got it. but why? I see that this might be a bit stiffer, but influence on cornering?

Edit: 4 linkers also have a virtual pivot point, like forks do. They feel quite nice IMO.
 
For me a well adapted wheelbase is more important than a suspension geometry.. Even 2cm is noticeable, so 20% would totally change the handling of the bike. The one thing I don't like about the motoped is the super long wheel base...
 
The motor could be swing arm mounted to totally remove any chain issues, but everyone is presuming it has to fit between the pivot and rear wheel, I don't remember seeing any rules that says it has to go there! Why not extend the swing arm into the frame and mount the motor on it in front of the pivot, still no chain issues and no compromise to the wheel base or suspension design. This way the motor could also counter balance the weight of the rear wheel making the suspension super responsive.

There are no rules, let your mind wander! The motor being only a 1/3 of the distance from the pivot as the wheel would only move a max of 2" for a 6" travel suspension.
 
Tench said:
Why not extend the swing arm into the frame and mount the motor on it in front of the pivot, still no chain issues and no compromise to the wheel base or suspension design. This way the motor could also counter balance the weight of the rear wheel making the suspension super responsive.
Click to expand...
There's a thread on this, here: http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=50973
 
Tench said:
The motor could be swing arm mounted to totally remove any chain issues, but everyone is presuming it has to fit between the pivot and rear wheel, I don't remember seeing any rules that says it has to go there! Why not extend the swing arm into the frame and mount the motor on it in front of the pivot, still no chain issues and no compromise to the wheel base or suspension design. This way the motor could also counter balance the weight of the rear wheel making the suspension super responsive.

There are no rules, let your mind wander! The motor being only a 1/3 of the distance from the pivot as the wheel would only move a max of 2" for a 6" travel suspension.
Click to expand...

I had that same vision last night whilst reading this but was too tired and lazy ( probably more the latter!) to post anything. Your 100% right on the counterbalance and speeding up the rear suspensions action. Could be the next great invention!

Now we just need a Guinea Pig to take the next step.....bzhwindtalker???

Tom
 
Miles said:
Tench said:
Why not extend the swing arm into the frame and mount the motor on it in front of the pivot, still no chain issues and no compromise to the wheel base or suspension design. This way the motor could also counter balance the weight of the rear wheel making the suspension super responsive.
Click to expand...
There's a thread on this, here: http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=50973
Click to expand...

Thanks for the link Miles, I had not seen that, off to read it!
 
I'm not too interested in reinventing suspension designs, I mostly want to build a very good and reliable platform to ride on. Most people on this forum would not really notice the difference in handling between a hub and a mid drive anyway, let alone between two suspension geometrys. I don't think I notice any difference myself between a well setup single pivot or 4link geometry. It's great if gys on the forum are researching on those subjects :)
 
Hey this is a great thread - subscribed.
 
HI Adam,

as you said me you want to move to 24"/26" on the LMX2 here a good price for tyre 24x3 (a little wider than the halo contra)
beetween 75 and 80mm with the 65mm RIM.
http://www.ebay.fr/itm/BANKRUPT-Pr-24-x-3-00-MOUNTAIN-BIKE-FAT-WIDE-TYRES-/380364293657?pt=UK_sportsleisure_cycling_bikeparts_SR&hash=item588f7a8619
http://www.bankruptsurplus.co.uk/PAIR-24-x-3-00-MOUNTAIN-BIKE-FAT-WIDE-TYRES-IN-BLACK_A11QN0.aspx
http://www.doggriderz.com/cerclesjantes-roues-de-velo/2051-cercle-24-alu-56-mm.html
 
crossbreak said:
that one is hard to cool.. there is a reason he prefered a well coolded 5kg inrunner over a 10kg not cooled outrunner :D
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Exactly. As I am after maximum brust power/weigth ratio a big heavy hub does not really make sense!
Plus I want to keep the bike narrow and agile. Jhon's hub with axle is 200mm wide! the bike as drawn here is 160mm. I have no interest in building something to compete with say a KX85 because at 76kg and 28hp it's hard to do with an electric for any meaningfull length of time below 10k€, and would not fit my goal of a go-anywhere, ligthweigth freeride bike.
 
dan974 said:
HI Adam,

as you said me you want to move to 24"/26" on the LMX2 here a good price for tyre 24x3 (a little wider than the halo contra)
beetween 75 and 80mm with the 65mm RIM.
http://www.ebay.fr/itm/BANKRUPT-Pr-24-x-3-00-MOUNTAIN-BIKE-FAT-WIDE-TYRES-/380364293657?pt=UK_sportsleisure_cycling_bikeparts_SR&hash=item588f7a8619
http://www.bankruptsurplus.co.uk/PAIR-24-x-3-00-MOUNTAIN-BIKE-FAT-WIDE-TYRES-IN-BLACK_A11QN0.aspx
http://www.doggriderz.com/cerclesjantes-roues-de-velo/2051-cercle-24-alu-56-mm.html
Click to expand...

Thanks for the links! Looks like I will be able to build a killer rear wheel setup for 120-150€
I already have a duro leopard in 24"x3 but those tires you pointed are burnout worthy cheap :twisted:
 
Thanks for the links! Looks like I will be able to build a killer rear wheel setup for 120-150€
I already have a duro leopard in 24"x3 but those tires you pointed are burnout worthy cheap :twisted:[/quote]

they re like 5mm larger than the duro leopard which is the same as the halo contra, it seems that the 65mm rim is a little wide (the tyre is flatten and so would loose some grip on strong corner, but offer more traction =) (on the side of the vuela tusa is written 51-58mm rim width for info so I guess a 55 mm is perfect for 24x3" and it fit perfectly a 19" MX tube
Or I would recommand even a little thicker the kenda dh thickiest that I found, but not grispter option with it...
http://www.winstanleysbikes.co.uk/product/53931/Kenda_24Inch_Heavy_Duty_DH_Schrader_Innertube
and greyborg have a double disc hub if you wanna mount a 6 holes sprocket on any side :wink: plus cheaper same rims in 46/56/76mm for 20$ !!
http://issuu.com/zelenavozila/docs/zelenavozila
http://www.zelenavozila.com/#!catalog/c20q3
dnmfork5.jpg


and you can even have it laced :D
 
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