300 EC Supermoto conversion informations

[Antoine]

Hello Everyone !

I am new to this Forum and pretty surprised to see the success of Gasgas bikes all around the world !
To introduce myself briefly, I am a 24 year old French dude and I've been riding Gasgas bikes in the past but trial ones.
My new (and first) job brought me here :



If you zoom in, you'll discover a wonderful playground around the mountains. It would be a shame to not be riding here !

I've always had this old dream of a big two stroke supermoto on the road (the best bike I had was an Aprilia 125 MX with the Rotax engine) but I never took the step. Shame that the road legal 500 CR became quite pricy !

After serching for a while, I found that the Gasgas 300 EC could be the perfect fit. And I'd still have the possibility to switch back to enduro wheels and have fun in the dirt.

However, to use this bike on the road, I would need to know which rims can I adapt.

I've read a lot of posts about this subject but I couldn't find any actual dimensions. I even sent an email to Gasgas but didn't get any answer.

The idea here would be to get 17" wheels adapted easily without having to buy the 1000€ Gasgas ones :

http://www.motocrosscenter.com/shop/...400sm2510.html



So, if you guys could help me to sum up which rims from other brands can be adapted without mods that would be great.

If there is no precise list, the other option is to get the dimensions that have to be checked when buying a used set of rims.

I am looking for a GasGas model after 2007.

Could someone provide me those infos ? (Just ask me and I'll make a drawing of what I exactly need)

- Wheel axles diameters. I have been reading that the diameter changed somewhere in 2004. I think it is 20mm at the rear and front. Other brands may have 22mm or 25mm so this could be a problem.
- Width of the wheels hubs (from one bearing to another)
- Dimensions of the discs supports
- Dimensions of the rear sprocket support
- Width from the disc support to the sprocket support
- Width from the sprocket support to the next bearing

Or could life be easier : who managed to adapt a set of rims from another brand without modifications ?

Someone from this forum (Gassergrant) adapted CCM wheels without much mods, so I guess those wheels could be found on other bikes ?
Here is the thread : http://www.gasgasrider.org/forum/showthread.php?t=16956



I found the max width of the rims : 4.25 for the rear and 3.5 for the front.

For the rear tire, I found the info as well, it is 150 maximum, otherwise it will rub the swingarm.

The second point seems to be a big matter to me : the front chain sprocket.

Using such a bike on the road will require to adjust the transmission. The stock front sprocket being a 13 teeth, can I switch to a 15 without grinding the hydraulic clutch module ?



And why not a 16 ? Who would be able to give me some feedback of the right ratio to use with 17" rims to cruise comfy on the road at normal speeds ?

The 15 teeth is available here : https://www.3as-racing.com/A-242503-...x#.V1RyEUtu2Qs

I remember about reading some posts from Jeff on this forum. Jeff if you're around, do not hesitate to share your experience / feedbacks



Any other info about SM conversion on a 300 EC is welcome !

Btw, is there a key on post 2007 Gasgas ? I think there is a lock on the fork but no "ignition" key ?



Thanks a lot guys for your feedbacks and answers !

Greetings from France.

Antoine

[hadfield4wd]

Welcome. Where? My daughter is in France now on an internship. In St. Lo.

[pscook]

Keeping it short - Ignition switch is present on any of the EC300 with electric start, or you can install a switch into a non-e-start wiring loom if you have the capacity, or swap the non-e-start loom with an e-start wiring loom.

15 tooth CS sprocket won't fit, as a 14 tooth barely fits. I have a 2011 EC200, but the cases are the same from 2005 and up. If someone says a 15 will fit, I would like to see pictures and understand exactly how they installed the sprocket, short of removing the motor.

Regarding wheels: Warp 9 here in the states would be a good resource, they might be able to set you up with proper wheels for less than 1,000 Euro. Otherwise, expect to perform some sort of modifications to wheels or bike to get an off-brand set of wheels installed.

Good luck!

[Antoine]

Originally Posted by hadfield4wd

Welcome. Where? My daughter is in France now on an internship. In St. Lo.

In south west near Tarbes. St Lo is quite far away !

Originally Posted by pscook

Keeping it short - Ignition switch is present on any of the EC300 with electric start, or you can install a switch into a non-e-start wiring loom if you have the capacity, or swap the non-e-start loom with an e-start wiring loom.

15 tooth CS sprocket won't fit, as a 14 tooth barely fits. I have a 2011 EC200, but the cases are the same from 2005 and up. If someone says a 15 will fit, I would like to see pictures and understand exactly how they installed the sprocket, short of removing the motor.

Regarding wheels: Warp 9 here in the states would be a good resource, they might be able to set you up with proper wheels for less than 1,000 Euro. Otherwise, expect to perform some sort of modifications to wheels or bike to get an off-brand set of wheels installed.

Good luck!

Thanks for your answer.

Given that the bike will be between 2007 and 2010, it will not be an e-start so I will have to install a key.

Here he says that the sprocket is 15 teeth : https://www.youtube.com/watch?v=tPQ0j-2uGRw

Antoine

[Anders]

My son built a SM version of his 08 model 300. He was lucky enough to find a set of GG wheels locally.

I have not heard of other wheels that fit right in without modifications, but (almost) anything can be made to fit if you have access to a lathe and a milling machine

In general the front wheel will be pretty easy to do, while the rear is more difficult as you have to search for a wheel with (almost) the same distance between sprocket and brake disk as the originals.

I have several wheel sets for my bikes so I can make any measurements you need. I can do it this week, but am quite busy so it may take a few days.

I have done wheel conversions on other bikes (fitted a set of PVM magnesium rims intended for a Ducati TT2 to my Bimota Supermono) so I know what it takes.

Depending on what you find on the secondhand market, I think you'll eventually find that the wheels from Motocrosscenter actually are quite affordable. Remember that the price includes disks and sprocket and even tires.

Regarding the front sprocket I don't really see the point in going bigger than 14, as there are plenty of smaller rear sprockets available.

[Antoine]

Originally Posted by Anders

My son built a SM version of his 08 model 300. He was lucky enough to find a set of GG wheels locally.
http://www.gasgasrider.org/forum/pic...&pictureid=871
I have not heard of other wheels that fit right in without modifications, but (almost) anything can be made to fit if you have access to a lathe and a milling machine

In general the front wheel will be pretty easy to do, while the rear is more difficult as you have to search for a wheel with (almost) the same distance between sprocket and brake disk as the originals.

I have several wheel sets for my bikes so I can make any measurements you need. I can do it this week, but am quite busy so it may take a few days.

I have done wheel conversions on other bikes (fitted a set of PVM magnesium rims intended for a Ducati TT2 to my Bimota Supermono) so I know what it takes.

Depending on what you find on the secondhand market, I think you'll eventually find that the wheels from Motocrosscenter actually are quite affordable. Remember that the price includes disks and sprocket and even tires.

Regarding the front sprocket I don't really see the point in going bigger than 14, as there are plenty of smaller rear sprockets available.

Hey Anders !
Thanks for your thorough reply.

I do have access to a lathe so I can do bushings and things like that. The idea is that I just don't want to spend 2 months on it if it's too much work ^^

Thank you for your proposition, that's very kind ! I'll let you know which measurements I need if I go and check some wheels.
As you can see in this example : https://www.leboncoin.fr/equipement_...76.htm?ca=16_s (this is our "Gumtree" haha), even with brand new tires, I can get a set of rims for half the price of new ones. And they'll do the same job !

For the sprocket, I was a bit afraid that a small rear sprocket could eventually get the chain to touch the swing arm or the chain guide. Any thoughts about this ?

Thanks a lot

Antoine

[Anders]

The front axle is 25mm, the rear one is 20. The rest I can give you in a couple of days. I am not at home at the moment, will return home tomorrow night.

Also remember that the distance between the sprocket and brake disk mounting surfaces on the rear hub is important.

Sent fra min E5603 via Tapatalk

[Antoine]

Originally Posted by Anders

The front axle is 25mm, the rear one is 20. The rest I can give you in a couple of days. I am not at home at the moment, will return home tomorrow night.

Also remember that the distance between the sprocket and brake disk mounting surfaces on the rear hub is important.

Sent fra min E5603 via Tapatalk

25mm for the front ! Did not expected that Is it on your 2006 or 2015 EC200 ?
Thanks a lot.

Guys, do not hesitate to give me some other feedbacks on other Gasgas years

[Anders]

Originally Posted by Antoine

25mm for the front ! Did not expected that Is it on your 2006 or 2015 EC200 ?
Thanks a lot.

Guys, do not hesitate to give me some other feedbacks on other Gasgas years

It is 25mm on both 06 and 15. I think the 25mm axle was introduced around 02-03.
But don't panic (yet). There are some really low profile ball bearings out there, in case you start out with e.g. a japanese hub intended for 20mm.

Sent fra min E5603 via Tapatalk

[Anders]

Some measurements from my wheels. 06 and 15 wheels are interchangeable.
These measurements are taken with my caliper (fully analog) in a cold and dark(ish) shed, and may be a mm or two off in any direction. But I hope it is good enough for your needs just now. If you need 100% accuracy, I can try to do it better :-)

Front:
hub width is 100 mm. The brake disk is "outside" the hub, so the total width including the brake disk is a few mm more than 100. I didn't measure the width including spacers, but when you remove the spacers, the distance from bearing outside to bearing outside is approx. 83mm.

Rear:
total width including spacers: 170mm
hub width: 155mm
I didn't measure the width over just the bearings (as I did on the front), but I presume its around 140-145.
distance between inside of sprocket to inside of brake disk: 150

As I said earlier, the front is pretty easy to adapt. As long as you are willing to accept a few mm offset from the bike's center line it will be plug and play (with a new pair of distances). If needed, some sideways adjustment can be done by loosening spokes on one side and tightening on the other.

The challenge with the rear is that you need a hub where it's easy to get the correct distance between the sprocket and the brake disk by shimming either disk or sprocket out (the best is of course to find a hub with the same distance). It's starting to get nasty if you have a hub where the distance is too big in the first place. At the same time you'd like to get a hub that that places the rim close to the center of the bike.