Nikolay

Hi Guys,
I am interested in Tern Verge D9 with 451 mm wheels. Unfortunately, the Tern dealer in our country does not import the Verge line of bikes, so I need to purchase it online.
I want to install the largest possible tires on this bike; therefore, I would appreciate it if one of the forum members, that owns such a bike, could make a few measurements and advise me.
I need to know the tire clearance in the fork crown, at the seatstays bridge, and at the chainstays bridge, to estimate whether 44-451 tires will fit, preferably, with fenders. These tires are "Speed Booster Oversized" by VEE TIRE.
As well, I would be thankful if one could measure the wheelbase and the chainstays length.
Thank you in advance.

Ron Damon

You do realize that OS tires require OS rim wheels, right? Do you have such wheels?

Jipe

ETRTO451 is a bad wheel size, the choice of tires is much too limited !

jfouellette

I didn t know that size tire is available in 451. Vee has the speed booster at 1.4 inch (1 3/8). The 451 tires have very limited widths available (2 or 3) while 406 tires are available is many width. Both are considered 20 inch tires but require very different wheels. The 451 is popular for performance oriented mini velo and folding bikes.

Nikolay

Yes, I know. The 451 is typically available at widths of 28 mm and 37 mm. However, Vee Tire makes also 41-451 and 44-451 tires.
In our country, the railway company limits the wheel size of the folding bikes that may be taken during rush hours - their limit is 20". Since 451 mm are also marked as 20", this is the largest allowed size, and I prefer to have as largest wheel as possible.

Nikolay

Tern Verge family comes with 451 mm wheels, which are tagged by some tire manufacturers as OS20

Pinigis 

Something just doesn't seem right here. I went to the Vee Tire website and found that they are equating 20 x 1.75 tires with 41-451, under a category that they label as BMX tires. Maybe it's just me, but they seem to be mixing and matching standards. I emailed the company and will share their reply.

Nikolay

Hello Paul,
You are right, typically the 451 mm tires are not marked with decimal numbers in inches; i.e., they should be marked 20 x 1 3/4 instead of 20 x 1.75. The decimal numbers are reserved for 406 mm tires.
I believe the description of B41145-OS tire is correct, as 1.6"=41 mm. Therefore, I believe that there is a mistake in ETRTO of B41144-OS tire, it, probably, should be 44-451, as 1.75"=44 mm.

I will be waiting for Vee Tire's reply to your question.

Thanks!

Jipe

You shouldn't focus on wheel diameter that much.

Tire width is more important for comfort than wheel diameter.

A 50x406 or 55x406 is better than a 41-451 or 44-451.

And BMX tires aren't a good choice for an commuting bike that will ride everywhere.

Nikolay

The wheel diameter has a significant impact on bike stability/lack of twitchiness, due to the increased gyroscopic effect. I ride on a relatively smooth surface, so 44 mm width is good enough for me.
Considering the "BMX tires aren't a good choice for a commuting bike that will ride everywhere", I guess you mean puncture resistance issue. Tioga's OS20 tires, indeed, lack any puncture protection; however, B41144-OS tires by Vee Tire have a kevlar belt, so they, hopefully, should have a similar protection level to V-guard by Schwalbe.

Ron Damon

"Twitchiness" is a function of several factors, including fork and frame geometry. You can't shouldn't focus exclusively on wheel size. Rest assured bike manufacturers adapt frame mindful of straight line stability and wheel size. The most expertise in this regard is 406 given it's overwhelming prevalence. You have a lot of experience on this channel, including from those of us who have ridden both 406 and 451 wheels extensively. 406 is not significantly more "twitchy" than 451.

Jipe

I fully agree with Ron, the main factor is the frame geometry, not the wheel size and especially not a relatively small wheel diameter difference as between ETRTO451 and ETRTO406 (and an ETRTO406 wheel with wide tire is very close in overall diameter to an ETRTO451 wheel with narrow/medium width tires, that's why both are called 20").

I have a Birdy for which I had 3 different wheel sizes, ETRTO349, ETRTO355 and ETRTO406 and there is no real difference due to the wheel size, what makes a difference is tire type and tire width.

Nikolay

OK, then I would like to explore the versatility of Tern Verge: the amount of clearance to install 50-406 tires. In such a case, I may get a bike with two wheelsets: 451 mm rims and 406 mm rims; one with speedier 37-451 or 44-451 tires, and the other one with cushier 50-406 tires.
In any case, Tern Verge has a longer wheelbase, compared to other 406 mm folders, so it should be more stable.
Therefore, I would appreciate it if one of the forum members that owns the Tern Verge could measure its tire clearance, both radially, and sideways.

Reddleman

Can’t help you with measurements, but I’ve seen folks online who own both Tern Verge D9s (skinny 451s) and Vectrons (406s with Big Apples) use their Vectron wheel sets on their Verges without changing tyres.

Nikolay

Thanks! That is valuable information.

Fentuz

If the OP verge is a later version with disc brake, then like gravel people use a set of 451 (like 700c) with roady slick tyres for speed and 406 (like 650b) with large volume tyres for all road/way applications. All advices about 50+ 406 tyres are good (28-451 and 50-406 are pretty much the same diameter some the geometry impact should be negligible) however, the rim size has not been mentioned.
451 rims are likely to be i17 or i19 (internal width) which works well with 25c to 38c tyres. With the 406, you would be better with i23 if you intent to fit 50c or 55c (big apple or big ben for example). I have mounted big apple 406-50 for i17 rims (20 spokes wheel) and i23 (36 spokes wheels) to see the difference and with the slimmer rim, the tyre bulges more and rolls side to side in corner. On the wider rim, it is very stable (as intended).
Per Schwalbe documentation, i17 and 50c is on the limit of acceptable fitment. i23and 50c is right in the middle.

https://www.schwalbe.com/files/schwa...ationen_EN.pdf

Jipe

Its true that a wider rim is better, however, ETRTO standard accept 50 or 55mm tires on the most common 19mm wide rims.

Nikolay

Thank you for the answers; though, the question about sufficient/insufficient frame & fork clearances to install 44-451 tires remains open.

Nikolay

Here is a shop that sells the 41-451: https://powersbmx.com/products/vee-r...31759235416157
The 44-451 are currently sold out: https://powersbmx.com/products/vee-r...31759235383389

Kabuto

Tern Verge X11 owner here. There's loads of clearance between the fork and front wheel and you'd easily fit a 41mm tire (don't think the fork is the same as that on the D9 though). Clearance is a little tighter between the rear wheel and the frame but there's still plenty of clearance (about 20-25mm to the seat stays and 18-20mm to the mudguard mount with 28/451 tires). I think a 41/451 tire would fit... just, but 44/451 would probably be too tight.

Nikolay

Thank you very much!

iamarunr

I am planning on getting the Verge X11. I am also intending to ride this on some gravel with 41/415 tires. How do you like the Verge X11. I have always wanted a folding bike and I have been very keen on getting the Verge X11.
Your input is much appreciated.

Kabuto

I like my Verge X11 a lot. Its not quite as fast as a road bike but its still pretty quick, faster than any other folding bike I've ridden hands down, and more importantly its a lot of fun to ride. But I would be very wary about using it (or any mid-frame folding bike) much on gravel. Smooth compact gravel every now and then... maybe. But anything more and I think you're going to place a lot of stress on the folding joints, causing accelerated wear over time.

willydstyle

Now you're making me want to get into mountain biking with a folding bike to test this out. Tern makes very solid hinges. I think if the hinge can handle the torsional stresses of a loaded ebike, as on their Vektron models, there's a good chance they can handle the stresses of off-road riding as well.

iamarunr

Thanks so much for your response. I really appreciate it.