A4X speculation

[Robert Holler]

Couple of questions :

• What's the BB spec needed ? BSA Threaded but what's the width? 68 or 73? (or more?).
• What kind of mounts for the brake calipers? Flat or post mounts?
• Wheels : what is the stock rim width? Model of the Chosen hubs? (if buying the full bike).
• Also related to wheels. Without going the custom built route, I can't seem to find a good source for a set of 650b wheels with 12x100 and 12x142 thru-axles. Gravel have the right hubs but almost always 700c. MTB is mostly 29in now (and usually boost). Getting 27.5 wheelset with a rear 12x142 non boost is easy but they usually come with 15x100 front hub. I know it's just a matter of putting an adapter to fit a smaller axle but I'm wonder if the frame has a notch or anything that would prevent the larger endcaps to fit? Can anyone at Cruzbike share a picture of the INSIDE of the rear "fork" ?

BB - 68MM English Thread

Brakes - calipers are DOA - there are "mounts" but the lust for wide/larger tires moves them too far away for calipers to be used (on ANY bikes) - the disc mounts are flat mount style.

Wheels - 142x12mm drive and 100x12mm rear. There is a notch there but I would have to check if it can accommodate 15mm caps for an adapter - give me a day to get a few pics of this Ill post one here.

 

[llavalle]

The order page goes live on the 17th. If you are on the email list you can get in on a few bonus "coupons" (not sure for the frame set though) so it is worth to sign up for that email ASAP.

I got the email with the sneak peek "Last chance to join A4x insiders" but the "click to join the insider" list never worked here for some reason. Where can we sign up?

BB - 68MM English Thread

Brakes - calipers are DOA - there are "mounts" but the lust for wide/larger tires moves them too far away for calipers to be used (on ANY bikes) - the disc mounts are flat mount style.

Wheels - 142x12mm drive and 100x12mm rear. There is a notch there but I would have to check if it can accommodate 15mm caps for an adapter - give me a day to get a few pics of this Ill post one here.

I meant disk brake caliper. Not "caliper brakes" . My question is the mount on the frame. Flat mounts (like gravel or road bike) or Post mount (like mtb).

For example, the TRP Spyke are Post Mount only. Caliper has "ears" where you put the screw and it's threaded in the frame.
The TRP Spyre (not Spyke!) are available in both Post and Flat mount.

Flat mount are bolted in differently - you put the screw in to the frame (or small adapter plate) and it threads into the caliper. No visible "ears".

Checking the pictures is hard to see. The caliper looks super close to the frame but pics are from the right side so hard to say.

Thanks for checking the notch. I've seen some that are only there to help you a bit when putting the wheel in but the notch isn't actually touching when the axle goes in. 12mm thru-axle hubs are usually have a 19mm OD on the end caps. 15mm usually have 21mm OD.

My question about the wheels you sell with the complete bike : what is the width of the RIM itself. Giving me an idea of which tire size I can put on there.

 

[llavalle]

As another example : the S40 uses flat mount disk calipers.

 

[llavalle]

Humm...

Just found this https://forum.cruzbike.com/threads/q45-700x32c.14546/
2 things in that thread :
-The rear of the Q45 fits the wider outer diameter of the 15x100 hub he used.
-700x32 left 12mm (1/2in) clearance between the tire and the fork / shock mount

This is VERY interesting
This means that if the rear of the frame on the A4X is the same (for the axle), it would also fit. This also means I could maybe pickup a set of 700C wheels with the actual 12x100 (if the clearance on the back of the A4X is the same)

I also found this :

Bicycle tire sizes tutorial and what tire and wheel size ranges fit each Cruzbike recumbent road bike model

Let's talk tires! In this post Robert answers some common questions about wheels, tires and fit on each Cruzbike recumbent road bike model: Why are some tire sizes measured in inches while others are measured in millimeters? What size tire can each Cruzbike model accommodate? Which Cruzbike...

cruzbike.com

(which was updated for the A4x!)

It states this :

• Cruzbike Q45 Adventure Bike - 650b stock wheels and can go to 40c
• Cruzbike A4x Adventure Bike - Stock 650b wheels accommodate tires up to 57mm (2.25") wide; swap to 24" wheels and clearance opens up to 68mm (2.6") for even more capable rubber on demanding terrain. Note: fender installation is not compatible at maximum tire width

Assuming tire width = tire height, from a pure math perspective, 650b with 57mm is exactly the same as 700c with 38mm tires.

The math :
Bead seat diameter of a 650b is 584mm. Add 2x 57 and you get a total wheel diameter of 698mm
Bead seat diameter of a 700c is 622mm. Add 2x 38 and you get the same wheel diameter of 698mm
Did the same math with the 24in wheels but I assume the limitation in that case is the width, not the diameter.

I know this isn't exact at all but I have 700c wheelset I could test

And lastly - Modifying the end caps of a 15x100 hub seems pretty easy. Chuck it in a late and reduce the OD from 21 to 19mm. Then install a 12mm to 15mm adapter shaft in there for the proper axle diameter.

Alright, when can I order this frameset and get started on my build? (I know, I know, March 17th!)

 

[llavalle]

The order page goes live on the 17th. If you are on the email list you can get in on a few bonus "coupons" (not sure for the frame set though) so it is worth to sign up for that email ASAP.

Alright, we had enough rain to melt the snow. First ride on my Optima Cougar - after less than 3min I was able to do this! I'm sold.

Watch Cam Avant 3-16-2026, 18.55.30 EDT - 3-16-2026, 18.55.45 EDT | Streamable

Watch "Cam Avant 3-16-2026, 18.55.30 EDT - 3-16-2026, 18.55.45 EDT" on Streamable.

streamable.com

So we're talking tonight at 11:59PM or like 9AM tomorrow ?

NVM, the email says "The all-new adventure bike opens for orders 3/17 at 10 a.m. EDT"

Bronze or Blue?

 

[Damien]

"I really love the design – you definitely won't mistake this bike for any other. Great job! Hope it sells well. I’m personally a bit skeptical about FWD (front-wheel drive) off-road, though.

 

[Boreen bimbler]

"I really love the design – you definitely won't mistake this bike for any other. Great job! Hope it sells well. I’m personally a bit skeptical about FWD (front-wheel drive) off-road, though.

I've ridden my S40 off road. It certainly had it's limits (as you can't stand up obviously) but it was suprisingly capable. A bit of suspension would have made a great difference in comfort and wider tyres than my 38mm would help too. So I think the A4x should be pretty good on tracks and paths. Maybe don't take the black routes though.

 

[llavalle]

Alright, we had enough rain to melt the snow. First ride on my Optima Cougar - after less than 3min I was able to do this! I'm sold.

Watch Cam Avant 3-16-2026, 18.55.30 EDT - 3-16-2026, 18.55.45 EDT | Streamable

Watch "Cam Avant 3-16-2026, 18.55.30 EDT - 3-16-2026, 18.55.45 EDT" on Streamable.

streamable.com

So we're talking tonight at 11:59PM or like 9AM tomorrow ?

NVM, the email says "The all-new adventure bike opens for orders 3/17 at 10 a.m. EDT"

Bronze or Blue?

Ordered! (Bronze frameset + a few accessories like a spare droupout, the A4X frame bag and the ventisit seat)

Can't wait to build it and ride it!

 

[Robert Holler]

It does not appear to me that there is room in the dropout notch for a 15mm hub cap. Also pics of the brake mounts - flat mount with both front and rear using the same adapter (this is the same as on the Q and the S.

Robert

 

[llavalle]

It does not appear to me that there is room in the dropout notch for a 15mm hub cap. Also pics of the brake mounts - flat mount with both front and rear using the same adapter (this is the same as on the Q and the S.

Robert

Thanks for following up.

Indeed - that looks tight. Just ordered the frameset, I'll take full detailed measurements when it gets here.

Perfect for the brakes!

 

[Elisa]

I am wondering where do you place the water bottle for access while riding? This is an issue with the Q45. On my Q I have placed it on the boom with velcro attachment.

 

[Robert Holler]

I am wondering where do you place the water bottle for access while riding? This is an issue with the Q45. On my Q I have placed it on the boom with velcro attachment.

Mounting to the back of the seat with the spacer works great. Personally I drill lower holes for an easier reach.

 

[Elisa]

Mounting to the back of the seat with the spacer works great. Personally I drill lower holes for an easier reach.

It is a difficult/awkward reach when riding