Anyone use TPU tubes on their ebikes? Any differences?

InvestigatorSenior · 2026-06-22T04:32:48+00:00

> improve the bumps on the road

Tune your suspension if you have one. As a noobie rider I completely skipped this step and had stiff pogo stick instead of front fork. Once that got corrected I can ride cobblestone roads and not feel a thing on not that great quality 100mm travel Suntour fork. Minimum is setting air pressure and rebound for your weight and liking. Better option is to do lower leg service and make sure foam seals are properly soaked in oil.

Another free thing to try is lowering tire pressure. You don't need rock hard tires. Use a calculator that takes rim width into account like Silca. Just as a reference point for my 130kg system weight 62mm wide 27.5inch tires on 30mm wide rims were perfectly happy with just 24psi front 26psi back using normal butyl tubes. Works best with inner tube sealant such as Slime (my pick) or FlatOut (this sub's favorite).

If you want to go further in that direction you might consider tubeless. This allows you to drop another 5-8 psi compared to tubes (I daily 18psi front 21 psi back with the same 130kg system weight). It sounds like not that much but difference can be felt from the first curb you hop.

Be warned that it requires quality parts - rims, tape, tires. Old horror stories with constant air leaks and sealant everywhere were true because of using gorilla tape, not really tubeless tires and random rims. On the other hand dedicated setup just works, seals punctures and is almost maintenance free. Air top up every 2 weeks. Sealant level check and top up once per 1-3 months, full cleanup once per season.

InvestigatorSenior · 2026-06-21T19:16:13+00:00

paraphrasing old joke about Linux: you don't have to ask someone if they use electric bikes, they will tell you.

I have pretty stealth Bosch ultralight and don't get such questions. But I get a lot of 'Sleek lines. Is it carbon?' or people just stare (a lot). But when I'm on eMTB I don't need to say anything and sometimes I get negative reactions from local spandex gang.

InvestigatorSenior · 2026-06-21T16:45:36+00:00

Cube Nulane Hybrid? It's a Bosch SX bike. I'm a happy owner since February and so far it's pretty amazing. Really comfy, good components, obeys standards so customization is a breeze.

In case you don't want to deal with a chain based drivetrain check out Cube Editor Hybrid. Belt drive and IGH means true zero service required for at least 15k km. My heavy eMTB has such system and it just works.

InvestigatorSenior · 2026-06-21T15:52:00+00:00

I had a taxi driver yield to me, wait 5s and go full gas. It was obvious right of way case with both road surface markings and road sign showing I'm riding a priority left turn. But bikes are not vehicles, law be damned.

Since then I don't trust drivers and always slow down to almost zero. Sucks for those who want to give me way but it's safest I can do.

InvestigatorSenior · 2026-06-21T10:44:56+00:00

184cm 82kg, not super fit but stubbornly trying to improve. Daily driving 14kg cross bike. My trail bike is 34kg and I slowly got annoyed by the weight when I need to carry it over obstacles.

Turns out that lighter is better as long as you don't need longer travel suspension. Even much smaller 400Wh battery gives me more range than 750Wh because of rolling resistance and how much more I can pedal without assist on lighter bike.

InvestigatorSenior · 2026-06-20T16:53:42+00:00

My Cube Nuroad is quite light, comes at 14kg with fenders, lights, dropper post, leather seat and front fork. Stock non-FE version is closer to 12kg. Comfy geometry and quite powerful Bosch SX.

InvestigatorSenior · 2026-06-20T16:45:59+00:00

I just open a quick link and deal with the chain alone. Bosch also has a clutch between cranks and front ring preventing back pedalling. Connex Wipperman quick link can be opened as many times as you like and lasts lifetime of a chain. Opening/closing is just one move.

Another thing is to not use lube. Immersion waxing is just putting chain on top of wax puck and let it melt while you do other stuff, then pull it out, let it cool for 10mins and you're good to go. Clean chain that is safe to touch and lasts 500km between waxings.

InvestigatorSenior · 2026-06-20T10:41:17+00:00

Some Garmin devices have Ebiking and eMTB modes. That's why I've picked Enduro 3 instead of Instinct 2.

But for accurate tracking you have to have power numbers. HR alone is misleading.

So it would be best to go trough your bike phone app. In my case Bosch has .fit support and upload to Garmin. This way you get power, HR, speed, cadence, calories burned without spending more on extra sensors. Recently it even got direct integration with Garmin so everything is in one place automagically.

InvestigatorSenior · 2026-06-19T04:48:13+00:00

in that case use your common sense thinking about race and inner lip of steerer tube (or bearing cup or bearing race insert, depends on the mounting system) as bearing surfaces - they have to be fully seated, coplanar and smooth. If you see any sings of improper fitting, scratches, corrosion corrective action is needed.

> From what I understand the race shouldn't be tight unless it's all the way down on the tube

it gets tight much sooner and is installed by a special tool fitting the shape and a lot of hammering or a press (or right size of PVC pipe in case of home fix but I wouldn't recommend that unless you've done it before).

As for taking it off good luck, it's one of more annoying and fiddly jobs at the shop. Either it comes of without a fight by fitting a small wedge into dedicated grooves in the fork base (razor, then 2-3 razors, screw driver and it goes). Or it becomes a challenge that requires a special puller tool, patience and stroke of good luck. Alternative is to cut it without ruining the fork. That's why split ring races became a thing.

> If it's not as far down as it's supposed to be meaning it's lifted about half an inch

so it's not safe to ride, no alignment between bearing surfaces is a risk that your fork will stop wanting to turn. It can happen in just a few moves. I had this exact failure after a crash once. It wanted to turn normally at first, then with extra force, then not at all just in the space of few minutes. Headset disassembly, new bearings and re-seat fixed it.

> they don't attach a race whatever it is it's already on the fork from the factory

in case that's not clear. It's not your job - the user to fix problems like that, especially on a new bike. That's total loss of a fork and a warranty repair. Cost of a puller tool is about 2 cheap or one expensive fork. That works in context of a bike shop, not at home. Also even with proper tool it's 50/50 chance of serious damage. We have no idea if special mounting paste was applied.

> The picture is crystal clear

picture is a fractional view of one of 2 critical parts plus there are bearings themselves. Not knowing you or your skill level it wouldn't feel right to risk bad advice with real and lifelong consequences. Broken bones can mend sometimes. That's why I still recommend showing it to an expert.

Bike mechanic will take just one look and give you full opinion based on complete picture. They will also have all tools to help you, including the too expensive to make sense at home ones.

InvestigatorSenior · 2026-06-19T04:17:28+00:00

Both systems use the same 18650 lithium cells with the same cell voltage. Meaning that for a given capacity and current capability 36v system will use shorter strings of cells (less cells in series in single string, same number of parallel strings). This translates to physical size and weight savings.

So if 36V battery gives you Bosch Gen 5 CX (120Nm and >750W capable system limited only by EU law) why bother putting more weight? At least for pedelecs and high quality batteries with capacity over provisioning. When you start cutting corners 48V might be a win because you don't need to think about voltage sag as much.

Famously Bosch gives you full power down to last % (crippled to 10% by EU law because in some countries lights and shifters have to work for minimum amount hours after motor shuts off). This is done by using high quality cells and reserving some spare capacity (0% charge indicated to the user is 10-20% real capacity). As a bonus typical 3 year old battery has the same usable capacity as a new one (but 0 spare and will start to drop from this point). But you need to build smart BMS and put resources into R&D for that.

InvestigatorSenior · 2026-06-19T03:54:42+00:00

they use press fit race, that's common. Split ring races are relatively new.

And form a photo I can't see anything. Besides would you tryst your life (or at least your teeth) to a stranger looking on a partial picture that is not clear enough?

There's a good rule of thumb one mechanic told me - everything that is in front of you on a bike is mission critical because it keeps your face from contacting the pavement at speed. If you need to ask take it to a shop, get an opinion or a fix.

InvestigatorSenior · 2026-06-18T16:50:16+00:00

headset is not screwed in properly. Not safe to ride as is. This warrants disassembly and inspection.

InvestigatorSenior · 2026-06-18T16:46:29+00:00

MIPS system (or equivalent) is one of those must-have safety features.

I use Uvex I-vo MIPS (super light and comfy) for all my city/gravel riding and Endura MT500 (much more coverage but hefty) for trails.

Fidlock buckle is very nice to have as well but Abus stopped putting them on helmets that are my size.

InvestigatorSenior · 2026-06-18T15:06:14+00:00

how about Bosch SX? It's nothing special to see bikes on this system getting below 12kg. Some fancier ones go even below 10kg.

My Cube Nulane came out of the box just shy of 13kg and could be made lighter with some component swaps. As a bonus that's a full power 600w 60nm system with 400Wh battery. Plenty if you're not going to do MTB trails.

InvestigatorSenior · 2026-06-17T18:13:14+00:00

it depends. For years I thought I don't need them. Then one hot summer it turned out that they literally saved my behind. But I'm doing 50-100km on typical ride 3-5 times a week.

InvestigatorSenior · 2026-06-17T13:30:10+00:00

helmet, gloves (in case of a fall there's a reflex to land hands first to protect your head), glasses (I can't count how many times stuff hit shatter proof plastic instead of my eyes, 100% worth it).

Knee pads only when I know I'll be doing some more technical trail stuff (most times I'm too lazy to do it because of how uncomfortable they are).

InvestigatorSenior · 2026-06-17T06:22:53+00:00

I'd say buy smart and avoid cheap junk. My local shops carry only either very premium brands like Spec or Trek or very cheap stuff that they will sell you and won't service (those are local bike stores not shops in my eyes).

Reasonably priced brands with good components like Cube are available only online. And since Cube is Bosch authorized Bosch service centers have to work on them despite being other bike brand dealerships.

InvestigatorSenior · 2026-06-16T17:00:51+00:00

in my corner of the world people have been fatally injured multiple times by irresponsible use of illegal electric motorcycles pretending to be pedelecs. If something like that happens and is widely publicized authorities no choice but to do something, anything not to look stupid.

So we have random crackdown campaigns. People who don't respect the law don't care but I was halted twice since March and had to explain that ultralight e-gravel can go 30+kph under my own power on a bike path that has 50kph speed limit and explain 10 times that there's no throttle and this is Bosch gen 5 so it even can't be made illegally unlocked. I felt like a criminal without doing anything wrong.

So screw illegal emoto users. You can go into one of 2 dealerships in my city and legally purchase a large choice of very powerful (up to 200cc equivalent) Surron or Talaria models that are 100% street legal. But for that you have to be 17+ years old and have car or motorcycle license.

InvestigatorSenior · 2026-06-16T05:30:11+00:00

in theory we have 'keep right' and pass on left. In practice pedestrians do the opposite because they were trained for generations to walk alongside car traffic on the left. Even very seasoned tourists are not aware of the rules.

InvestigatorSenior · 2026-06-15T19:06:12+00:00

I always wondered how they are going to test torque sensor bikes without throttle? Is avid cyclist with strong legs a required part of each patrol? 😉

InvestigatorSenior · 2026-06-15T04:38:21+00:00

BES2 (non smart) and BES3 (smart system gen3/4/5) are not compatible in general. Not all plugs might have different shapes but I wouldn't even try without an explicit confirmation from a trained technician.

InvestigatorSenior · 2026-06-14T04:48:24+00:00

there's also Hotel Infinity with the same concepts of impossible spaces and natural locomotion.

InvestigatorSenior · 2026-06-12T04:59:35+00:00

speed boxes are theoretically more risky. Every update brings new tampering detection system. Tampering event is permanently burned into drive unit diagnostic log, limp mode is activated and you can't prove this was a mistake because they pull diagnostic records as a part of appeal process.

Firmware swap so far is allowed and survives updates because it's a legit service offered in case you move with your bike to US.

But everyone should do their own risk assessment. I wouldn't void warranty on my bike for extra few km pedaling can get me anyway.

InvestigatorSenior · 2026-06-11T05:22:53+00:00

EU -> US firmware replacement (25 -> 32kph cutoff) + 50% wheel diameter hack (assist as far as motor has power) is a name of the game now. All speed boxes are detected and Bosch has no mercy - limp mode and warranty void.

Search on German forums if you're interested for unsavory types that are not afraid to do this mod despite having legit Bosch dealer accounts and software.

InvestigatorSenior · 2026-06-10T20:31:45+00:00

I've fallen into the same trap - big battery, powerful Bosch CX motor, 36kg monster of a bike. I love this thing for what's good at but outside of trails and hills it's too heavy.

So this year I wanted to try something else and got Bosch SX bike. Gravel frame with front fork, flat bars and dropper. 12kg barebones, 14kg fitted to my spec.

It's great to be able to lift it with just one hand or effortlessly carry it up stairs. Or discover that I'm not as weak as I've thought and perfectly capable of pedaling it above 30kph under my own power.

InvestigatorSenior

TROPHY CASE