Sur-Ron - New Mid drive Bike

[fechter]

Dang! fast enough.

I'm still rethinking my plate/rear light setup. I like how yours is more visible but not sure if it would interfere with getting on/off the bike or be something that could hurt you. I've been pulled over once and think maybe if my plate was more visible it would lower my chances of getting stopped again. Not that he did anything but I'd rather avoid potential problems.

 

[morati]

OK so I finally gave in and bought a Sur Ron last week. I think it's going to need some mods before I am happy with it. For those of you running a FOX 40 fork, what rake would suit this bike better (48mm or 52mm)?

 

[iliketurtles]

Thought I'd post an update as I got some really good advice earlier in the thread that helped me road-register my non-road-legal Sur Ron in the UK

There's a 'loophole' in the UK where if a bike fits certain dimensions, it doesn't have to go through a rigorous type approval process (which checks things like mirrors, makes sure your lights are the correct distance apart etc).

I was unable to get hold of a road legal bike at the start of 2020 so I went with the off-road one. The other benefit was having a simpler wiring loom without all of the road legal shenanigans.

My bike has a ~32.5cm ground clearance (12.7") and a seat height of 94cm or 37" - aka more clearance and a higher seat than my Husky 701

Mods required: 21" front wheel, Manitou Dorado + Drop upper crown (gives you about 1cm more space on the fork uppers so you can drop the forks in the lower crown), Seat extenders and rear progression link from Dan Orlov, Fox X2 on the rear which is very slightly longer than the stock shock (4mm I think?), and lastly the CST 186 3" tyre which is about 1.5" higher than the stock tyre.

Now that I can legally ride it on the road I've realised how much it needs a bit of extra oomph at ~40mph, especially after going to a 58t rear sprocket. Waiting listed for a Nuc 24f since January so hopefully that starts moving soon

 

[Offroader]

Look what I found, I will probably have to replace the whole rim. I am not sure what I hit to do that.

The odd thing is I don't feel it when I am riding.

 

[Hawaiiguy]

Hit a curb at speed?

 

[fechter]

You could try bending it back with some pieces of wood and a big C clamp. If that fails then you needed a new rim anyway.

 

[Offroader]

I may try that wood fix. The rim is probably bent in the middle also because the spoke was a bit loose right at the bend. Surprisingly the bike drives smooth and I can't tell the rim is bent.

I've hit so many things, and some things I didn't see in the grass that were really big. I also hit some things with my night driving.

As soon as this 18x1.6 rim comes back in stock I'm going to buy at least 2 of them. They are hard to get in this size and weight so I want to have a couple of backups.

 

[X-Nitro]

Waiting listed for a Nuc 24f since January so hopefully that starts moving soon

I signed up for a nuc controller on Mar3, glad to see I'm not the only customer forgotten by those guys.
Orlov & most of the other Easterners have moved on from nuc so I have now given up ever getting one & I'm shopping the alternatives.

 

[iliketurtles]

Waiting listed for a Nuc 24f since January so hopefully that starts moving soon

I signed up for a nuc controller on Mar3, glad to see I'm not the only customer forgotten by those guys.
Orlov & most of the other Easterners have moved on from nuc so I have now given up ever getting one & I'm shopping the alternatives.

Not forgotten - this is exactly why they don't ask for an upfront payment, because they can't guarantee delivery at any particular time. FWIW mine should be good to go in about a month (I actually ordered mid Feb, not January), so yours might be ready around the same time - it's definitely worth giving them a quick email to confirm.

That said, no real harm in buying another controller, running both and seeing which one you prefer, then selling the other - all the good controllers are hot ticket items so you won't lose much $ if any...

 

[Rix]

Look what I found, I will probably have to replace the whole rim. I am not sure what I hit to do that.

The odd thing is I don't feel it when I am riding.

Take a 2x4 about 12" long and a big heavy rubber mallet. Hit that thing until its straight. You will need to re-true your wheel afterwards.

 

[sn0wchyld]

Waiting listed for a Nuc 24f since January so hopefully that starts moving soon

I signed up for a nuc controller on Mar3, glad to see I'm not the only customer forgotten by those guys.
Orlov & most of the other Easterners have moved on from nuc so I have now given up ever getting one & I'm shopping the alternatives.

forgotten is not the case mate. I signed up for one late last year... got it early this year (precovid). bout 3-4months all up. They've become very popular in a time where supply has tanked (covid). pita to wait yea, but they're damn good controllers. I've ordered a 2nd 24f as a result.

 

[Offroader]

I wonder how many guys here have been running the nuclear 24fet? I surprisingly don't really see many people using them here or posting about them.

I've been using mine for a while now, the whole summer, but I got on the pre-order like the first week they started it.

You will notice a greatly improved power and acceleration, little more top speed with the stock battery, insane more power and top speed with a battery upgrade. You will also get regenerative braking and a much higher quality display.

 

[iliketurtles]

I saw someone who mounted their 24f inside the stock sur ron controller heatsink. I might have to buy a dud controller to try that, I love the look of the stock controller.

I think most people with the 24f's have 'completed' the Sur Ron upgrade journey and have moved on to riding the thing :lol:

 

[motomoto]

Rix wrote:

Take a 2x4 about 12" long and a big heavy rubber mallet. Hit that thing until its straight. You will need to re-true your wheel afterwards.

The 2X4 is right. The rubber mallet should be a big fat sledge hammer with a brave 2x4 holder.

 

[Amaxophobie]

I saw someone who mounted their 24f inside the stock sur ron controller heatsink. I might have to buy a dud controller to try that, I love the look of the stock controller.

I have done that too because of the looks. The "donator"-Controller had all his connectors cut directly after exiting the housing so it was pretty much useless anyway. Be sure to put the old controller in a bucket full of boiling water for ~20 minutes to make the potting compound more soft. At room temperatur its hard as a block of plastic. Using the oven for it is also a possibility but I was concerned about having hemicals in my lasagne later that day :lol:

The Nuc 24F fits perfect under the original casing. No modifications needed, except for a simplemounting bracket on the lower part.

As you can see I even used the original plastic sidewalls so there's no way you can see the nuc from outside. This comes with the con of overheating on warm days in combination with a 20s15p battery due to literally no airflow on the controller housing. So I might remove the side plastics in the future..

 

[iliketurtles]

I saw someone who mounted their 24f inside the stock sur ron controller heatsink. I might have to buy a dud controller to try that, I love the look of the stock controller.

I have done that too because of the looks. The "donator"-Controller had all his connectors cut directly after exiting the housing so it was pretty much useless anyway. Be sure to put the old controller in a bucket full of boiling water for ~20 minutes to make the potting compound more soft. At room temperatur its hard as a block of plastic. Using the oven for it is also a possibility but I was concerned about having hemicals in my lasagne later that day :lol:

The Nuc 24F fits perfect under the original casing. No modifications needed, except for a simplemounting bracket on the lower part.

As you can see I even used the original plastic sidewalls so there's no way you can see the nuc from outside. This comes with the con of overheating on warm days in combination with a 20s15p battery due to literally no airflow on the controller housing. So I might remove the side plastics in the future..

Thanks, this is AWESOME information, particularly how to deal with the potting

I wonder if maybe thermal pasting the Nuc 24f case to the plate inside the stock housing would help? Although the 24f case appears to be heatsink-ified anyway so probably end up wasting a ton of thermal paste :|

 

[Amaxophobie]

I wonder if maybe thermal pasting the Nuc 24f case to the plate inside the stock housing would help?

The FETs in the Nuc are sitting on the two sidewalls so I guess this wouldn't help much.

With the stock battery I had no problems at all with heat. But with peaks of nearly 21kw the 24F starts sweating in there. I bet removing the plastic side panels solves this "issue" right away!

 

[pipeking]

I do know many guys use 27.5" forks but I don't think they are pushing the bike extremely hard off-road and are not as sensitive as I am to the handling.

Please. I have hucked mine off some pretty big drops. I'll see if I can find some pics

 

[Offroader]

I wonder if maybe thermal pasting the Nuc 24f case to the plate inside the stock housing would help?

The FETs in the Nuc are sitting on the two sidewalls so I guess this wouldn't help much.

With the stock battery I had no problems at all with heat. But with peaks of nearly 21kw the 24F starts sweating in there. I bet removing the plastic side panels solves this "issue" right away!

I bought an extra sur-ron controller to mount my nuclear 24fet into. I decided against it because I didn't like the idea of putting a controller in a case and figured it would be better to have it cooled and less weight. Many have said the controller doesn't get hot so it doesn't matter, but in your case pushing that kind of power will be an issue.

Nuclear actually made a few controllers with the fets and controller mounted properly inside a sur-ron controller, Alex here was lucky enough to buy one of them. But it became cost prohibitive and not worth the time and effort to custom make them like that. I tried to convince them otherwise but it wasn't going to happen. I even suggested making the nuclear controller in a DIY kit so I could mount it myself inside the sur-ron controller case but they didn't want to go for that either.

I would say that you will barely notice the controller in that location unless you are really looking at it. I wouldn't bother mounting the controller in the sur-ron controller for looks, as nobody will ever notice it.

 

[Offroader]

I do know many guys use 27.5" forks but I don't think they are pushing the bike extremely hard off-road and are not as sensitive as I am to the handling.

Please. I have hucked mine off some pretty big drops. I'll see if I can find some pics

Just to clarify things with this. I'm not talking about strength or rigidity of using a 27.5" on the bike. I'm specifically talking about changing the geometry of the bike which will make subtle changes to the handling of the bike.

Since I don't have the luxury of trying out different sized forks to see if there is a difference I can only go by what I have read. It does seem that the changes from a 26" to a 27.5" are too small to make a difference so it probably doesn't really matter, but the opinions are a little mixed.

A 27.5" will have a larger offset than a 26", it may also raise the front of the bike slightly, it may also change head tube angle. Some of the newer fox 27.5" forks are now coming out with a shorter offset than they did last year, so if you bought last year fox fork it will have a higher offset which will be more noticable.

A 27.5" may actually offer better higher speed performance, but may hurt lower speed. Low speed handling and turning feel are just as important to me as higher speed riding.



What I'm saying is I just don't know what these changes will do and bike frames are made with a particular sized fork in mind. Geometry is a big thing in the downhill bike racing community. They discuss all these geometry changes. I also know when going from my sur-ron to my other ebike, I can feel the sur-ron seems to feel just right and I don't want to mess around with it. I would think that the original designers of the bike, which made such an excellent bike, put a lot of thought into the correct sizes of tires and geometry.

My point of bringing this all up is that there may be changes in the bike feel and handling by changing things out and that this is highly discussed stuff in the downhill biking community which our bikes geometry are mostly taken from downhill biking as we use the suspension components from downhill biking. I really don't know much about this as I don't have the luxury of many forks in different sizes to try this stuff all out so I err on the side of caution here. I don't want to buy a $1200 fox 27.5" fork to then feel that the front of the bike is raised a bit higher and something feels slightly off with the bike.

I have never actually said this or that would be better, just trying to let you know that you will be changing things in the geometry with throwing different sized forks made for different sized frames on the bike. But it does seem that the changes between a 27.5 and 26" fork are not so drastic and you may get used to the changes very quickly and within a few rides it will feel normal to you.

I don't know why I'm even bringing this up to be honest because I bought the last forks fox made in 26", and then bought another brand 26" fork for my bike. I'm sitting on two 26" forks and I'm set for a long time or at least until the next sur-ron version comes out. If I had a choice between a 26" and 27.5" fork of the same model I would personally go for the 26" version to play it safe.

 

[Rix]

Rix wrote:

Take a 2x4 about 12" long and a big heavy rubber mallet. Hit that thing until its straight. You will need to re-true your wheel afterwards.

The 2X4 is right. The rubber mallet should be a big fat sledge hammer with a brave 2x4 holder.

My rubber mallet isn't actually rubber, its a dead blow hammer with a nylon surrounded steel striking face. But yah, I get your drift.

 

[Hawaiiguy]

I have the 2020 Fox 40 27.5 and it handles awesome and has better fender clearance.I can’t imagine riding hardcore trails with a thumb throttle,maybe we have a different idea on hardcore off-road riding.

 

[Offroader]

First, please explain how a twist throttle helps you ride more difficult trails than a thumb throttle? I already went through this, the thumb throttle is superior because your hand has a firm grip on the handlebar, giving you precise throttle control at all speeds of riding while covering the brakes, sitting or standing, while getting thrown around and bumped around. I can even lift the front of the bike up while engaging the thumb throttle. A twist throttle does not give you a firm grip because the throttle twists in your hand, its simple physics, a permanent mounted hand position that does not move is going to give you superior control. From using both, twist and thumb throttle, I found the twist throttle allowed me greatly improved control of the bike, especially very slow technical riding where I need extreme precise control of the bike.

Think about it like this, do I want to put a handle on a hammer that swivels like a twist throttle? Or do I want a solid handle that doesn't move. Physics wins here just like it does with a thumb throttle. The thumb throttle is almost like you are controlling the throttle with your mind and your hands have total control over the steering of the bike.

So please explain to me how a twist throttle gives you more control when you are riding, I really want a convincing argument how having a grip on the bike that twists is superior to a grip that doesn't twist, and still allows you precise control of the throttle.

The 27.5" fox fork probably does handle awesome, but the question is how does it handle vs a 26" fox fork? I doubt you have tried both back to back and compared. You have no idea if they feel the same or different. This is what I question. Someone mentioned that the 27.5" fox 2019 or 2020 forks had a large offset and they actually lowered it in 2021.

From asking about this in the downhill biking forums, they say the 27.5" may feel a bit more twitchy because of the increased offset, but its not going to be that much of a difference and not worth worrying about, but it will cause changes.



For you guys who have no idea about geometry, please start reading about it, you will probably never understand it anyway, but you will at least know there is a lot of things go into this rather than the mentality, if it fits its good.

Granted, the sur-ron isn't a bicycle and you don't have to pedal, but it still has geometry and these things matter. Bike handling is not all about speed either as I do a lot of slow technical riding with the sur-ron and like a shaper turning, good low speed riding bike. By going with a 27.5 fox fork, you are increasing offset and I believe you will get a slacker head angle due to the increased size, which will give you a more low speed sloppy steering and harder to turn, something I really don't want at lower speeds.

I really recommend to watch this entire video as he touches up on so many aspects of geometry and many things I was talking about. I actually just googled this video and article today.

[youtube]0ZOFcO50D0A[/youtube]

Here is the article webpage.

https://www.worldwidecyclery.com/blogs/worldwide-cyclery-blog/video-fork-offset-explained-does-it-really-make-a-difference#:~:text=While%20a%20slack%20headtube%20increases,and%20slack%20head%20tube%20angle.

A paragraph from the article talking about geometry to give you an idea of how it changes things in the handling of the bike.

Back to our testing, riding the forks on bikes that were designed for them, of course feel great. Now we are putting them on bikes that originally were designed with the 51mm offset forks, bikes like the Yeti SB5.5, Evils The Wreckoning, new Devinci Troy and Santa Cruz Hightower LT, we found these bikes do have improvements with reduced offset forks. Does it handle like a new bike, no. But it does help with that cornering ability, straight-line stability and also slow down the front end feel a bit. These bikes are slacker and longer than what we were riding 3 years ago let alone 8+ when G2 came out. Once we put them on bikes that were steeper than 66 degrees, some XC bikes or mid travel bikes, we ended up with a more nervous feeling front end. While the trail was increased, it did not have enough headtube angle to compensate for the front wheel being closer to the body mass. As Chris Porter from GeoMetron bikes said “There’s no substitute for slack head angles”.

 

[Amaxophobie]

@Offroader

Is this how you drive around every day or was it just a picture after installation of the nucular (not nuclear ) controller?

I know it's a matter of taste but having the cables sticking out like this ruins the whole (closed) look of the bike in my opinion. And of course the protection against dirt and water. Maybe a custom 3D-printed cover would fit nicely?

 

[Offroader]

That video is really great discussing these things, especially the offset which is very high on the 27.5" fox fork. Normally 27.5" forks have a greater offset than 26" forks, but the fox 27.5" 40 forks had a really high offset.

What is interesting is what this guy says in the video about people being sensitive to these things. I find it interesting because I said I was sensitive to these changes, and I guess some people don't notice these changes and it depends on your body.

Watch the video at 9:00 minutes.
https://youtu.be/0ZOFcO50D0A?t=537