kais01

my 90s T5 with 44/305. It is surprisingly fast when surface is rough, rolling resistance of those Michelins is then comparatively good. A few weeks ago I passed two mamils; when they catched up two red lights later one of them really stared at the bike and asked where the motor is:-)
Have just worn out the rear rim so need to get another. Alu 28-spoke rims are hard to find.

kais01

for winter use mud flap could be even longer..

kais01

took a look at the brommies further up in the thread, both of them are likely to have widened fork and triangle; mine are stock. the 44/305s i use are wide enough to be decent on gravel, they also work fine in snow.

btw, in snow bike geometry reveals itself. slack 'modern mtb' geometry and too much trail creates self-steering, and such a bike may hopelessly steer and skid back and forth, as the rider tries to keep the bike on a narrow track/ridge of packed snow for example after a car or people walking. its not uncommon that such a bike just comes to a stop.

the brompton is here pretty good, and even better with the smaller 305 wheels having shorter trail. it runs best if the handlebars are tilted somewhat forward, as to have the effect of a stem. this goes with the 349s as well.

have to say, one of the greater assets of the brompton in my view are the standard tires. they have decent puncture protection, and roll unreasonably well on tarmac. have used my other brommies together with friends with serious racers in 20+ mph peleton club rides, and the difference in rolling is small, not to say minimal. they go best just under 4 bar.

so i would not convert my only brommie to 305s, but having one extra for hikes in terrain or snow is perfect. an extra bike is also handy to have as a backup, or for loan to friends and family

BromptonINrio

Woow!!
305 ultrawide tires on brompton?
Very nice idea!
How does it rides? Is is Stabble?

kais01

well they are not ultra wide, they are 44, though i think on the fat side for a 44. in this size all kinds of sluggish children bike tyres are abundant; but can really recommend the michelins. they roll fast, and the rubber compound is adhesive to snow and ice, not stiff and slippery.

the ride is very good i think. it is at least fast enough to keep up with or pass any number of mamils on mtbs and racers. i am pushing 60 myself btw, so i am older than most mamils. but i dont wear lycra when commuting

on the brompton as with any small wheel bike its beneficial to position the handlebars forward a bit, this adds stabilty and compensates for the lack of gyroscopic force in the wheels. i like to have them just a bit more forward than when i took the photo. on my summer bromptons i have lower bars angled forward about 45 degrees.

it is then stable also at speed, but as with any brompton with the added benefit of really quick steering response.

raftr

Neatly done, I didn't know there were cross tyres that fit on a 305 without modifying the frame elements.

tcs

The bead seat radius of the so called 18" size tire (ISO355mm) is just 3mm - 3mm! - greater than the so called 16" size tire (ISO349mm). It would be straightforward to convert a 349mm wheel bike to 355mm wheels and run the 50mm wide Schwalbe Big Apples available in that size IF the bike's frame/fork/brakes had the clearance.

tcs

There are plenty of pictures on the 'net of V-brake Mus (Mues?) fitted with Big Apples.

raftr

305 Big Apples more or less match standard 349 tires in outer radius, but there is no way they would have the clearance on 355.

That said, I think people put slicks on 355s on Bromptons, I recall seeing one here.

berlinonaut

What breaks are you using? I had assumed that the factory break arms would have a too short for 305 rims on the Brompton frame and at the same time the factory breaks not only have a reverse setup for fitting the cable to the break but also already far longer arms (more reach) than usual, so finding a 3rd party replacement with even more reach is not easy. It looks like dual pivot breaks which were not standard if your bike is from the 90s.

kais01

i bought a pair of front saccon brakes from friendly guy werner at funbikeshop in germany. their reach is up to 91 mm.

see i bought two front brakes, dont remember exactly why, but i think it matched better the brompton hardware on the rear. mounting was reibungslos.

saccon brakes are from an italian company, you may find them at ebay.it, but also ebay.de. their stopping power is ok, not more. but definitely better than pre99 brompton brakes.

kais01

here i found a good offer on the same brake, good thing they sell front brakes only.

FELGENBREMSE / SEITENZUGBREMSE / HANDBREMSE Synchron von SACCON 28x1.75 | eBay

jeanettebcrivel

I was look for this threat and finally got it. Great advice you all have share now I can surely do changes to my bike.

raftr

From my research, TEKTRO 900A slr and ALHONGA HJ-890A brakes should fit as well, but I haven't checked them out myself yet.

Also, SACCON SENCRO III 21/73 72/92 (they might be the same as kais01 used, model name is similar)

raftr

It's worth noting, the brakes need to have their cables routed upside down because of how the bike folds.
Not every brake allows for this cable direction swap.

kais01

well raftr, as is obvious from the photos above there was no problem reversing the pull of the saccon brakes.

i dont remember in detail why i opted to buy two front brakes, it is likely that its bolt length was better for mounting on the rear of the brommie. there might have been some minor tweaking necessary.

but nothing that kept me awake at night. as i said it was in all a smooth experience.

jur

The rear brake bolt is indeed very long. It also houses the seatpost stop.

raftr

Of course, I was just pointing out not all brakes had that option, if someone were to use a different brake model than Saccon for the conversion.

raftr

Two more examples of wider tires on 305s:




^ From Big Apple Rohloff Brompton - Kinetics (more photos)





^ From https://www.instagram.com/bike_vogue (many more photos of that one)

raftr

Both bikes above, I presume, have modified forks and rear triangles.

I found an older article about converting a Brompton to thicker tyres on 305 rims:

Off-road Brompton

berlinonaut

Just saw accidentally that the bike is currently for sale on ebay: Brompton Faltrad, Scheibenbremsen, 16" Big-Apple-Bereifung, 8-Gang Alfine, Motor | eBay

Modifications went on and it is now equipped with an H-stem with an additional Tern-Andros riser and the motor has been changed from a front wheel hub-motor to a velogical drive to save on weight. Really a very special beast.

Disclaimer: Not my bike and though I know the owner (but not the bike) I am by no means involved in the sale and found the auction by accident.

badmother

I like this thread

About brakes when converting- and also for a maintenance "free" solution I think hub brakes is not given enough credit. I remember many moons ago seing pictures of a B with a hub brake. Not sure about rim and tyre size on that one, not sure if the hub or the fork was modifyed.

If you are going for the 100mm fork in the front this should be straight forward installation.

In the rear I guess we are talking roller brake (if there is room for one) or drum, best on a 135 rear triangle.

Not the lightest but also disc brakes is not super light and if folding and unfolding a lot adjustment can be an issue with any brake- but I would guess the drum is the easyest to keep adjusted over time.

Maybe we can hope for some aftermarket ti parts for hub brakes so they can be lighter, like axel, brake arm, nuts and brake shoes? And if they go to all this trouble, why not make a light and narrower drum brake hub to fit the B, Dahon bikes and similar? In that case we could get hubs with the right amount of spoke holes too.The fact that it is old technology does not make it bad, just need a facelift.

https://chestercycling.worpress.com/...y/drum-brakes/

There is the one sided hub brake too that is used for trikes and stuff but then you need a one sided fork to use it and most folders can not use such a fork.

Edit: Found a wheel at: www.wrhpv.com/ukshop/hubbrakewheel/index.html
Looks like the hub is out of production.

leoho5

This bike is now up for auction on ebay Germany:

Brompton Faltrad, Scheibenbremsen, 16" Big-Apple-Bereifung, 8-Gang Alfine, Motor | eBay

Estuche

Can someone please identify these rims, or any other rims available today for use with 305mm Big Apples?

raftr

I studied this conversion back when the blog was still up and these are AlexRims DA16.

There are still some photos left here in this photostream:
https://ameblo.jp/yosiko2/image-1182...906919347.html

I could never find these rims in this size though, went for Litepro K-Fun, available via Aliexpress.
I'm in the middle of the conversion, have only done the front wheel so far, but the rim appears to be just fine for the job.

BTW, you will have a hard time finding Schwalbe Big Apple in 305, they are discontinued in this size. Look for Impac Bigpac, they are a cheaper version based on the old Big Apple tread, made by a Schwalbe subsidiary (I think). The downside will be lower puncture protection I suppose.