EvilV

It's been a long time since I posted here, even though I used to haunt the place.

One or two of you may remember how my 4000 mile Merc Brompton fake suffered a frame fracture at the top of the frame seat tube and had to be retired. I threw it in the shed in disgust and left it there for maybe four years and then dug it out and made a horrible 'repair' by drilling a hole through the alloy tube and the steel seat tube and putting a quick release bolt through the whole kaboodle. This makes it rideable, but maybe dangerous, as I am always worried that the frame will just break again and dump me on the street in front of a truck. Here's a picture of my suicidal repair.



As you can see, I'm no engineer.....



Anyway, although the old Merc rides OK so far, and is doing about ten miles a day, I am in the market for a new folder. I'd like a Brompton, but balk at the £1000 cost of a six speed in the spec I would want. I've been looking at the Tern D7i which is available new for £550 delivered and for about half of that second hand on ebay.

How do you people rate the Tern internal hub D7i in comparison to the Brompton?

I like the fact that the Brompton is all steel which gives me confidence that it won't break like the old Merc did, but I suspect that the Tern D7i may be a better and more efficient ride than the B, but it clearly doesn't keep its value second hand as well as the B. The other thing is that I need it not to break its frame with hard riding. The long steel seat post puts a heck of a strain on the 6061 Alu frame where it enters the frame structure. I weigh about 175 180 pounds but I do a fair bit of riding when I'm in the mood.

All comments welcome, but especially so if you've ridden and owned a Tern D7i or sold or serviced them.

Many thanks.


EvilV (Tony)

mulleady

Get your old Moulton back off Sesamecrunch! Hel left the fold and rides recumbents now lol!

You old scoundrel! Haven't been on here in ages then you appear haha!

PS

Look how my Brommy evolved lol!

https://www.bikeforums.net/showthread...speed-Brompton!

mulleady

Get the Brompton 6 speed on eBay. If you are patient you can get a bargain like this:

https://www.ebay.co.uk/itm/BROMPTON-F...item4175a28a71

Just had a few mouse nibbles!

mulleady

Or stretch your wee budget and get this stunner!:
https://www.ebay.co.uk/itm/1812032364...84.m1423.l2649

kamtsa

The Brompton has wider gear range (x3 vs x2.5).

Did you test ride the D7i? How did you like it?

EvilV

Ha ha - nice to see you are still here you old scoundrel Mulleady! )

How are you doing?

The Raw Lacquer B looks fabulous still. I am surprised that the mighty Mulleady calfs have not snapped it in half by now. It must be a great ride with the Alfine hub. Enjoy it. I was just thinking about you and your fab bike the other day when I started looking for second hand Brommies.

They seem to be going at £550 to £650 for examples with varying amounts of scratches and weather damage. I'm just cautious about not piling money into a bike that has been hammered like my old fake B.

I suppose you haven't any experience of the Tern D7i? I kind of feel I might be better off putting £550 into a new one of those than a well hammered Brompton. I am just completely unsure which way to go, but if a super bargain came up, I'd be tempted.

brakemeister

get what you really want and than have no regrets .... BUT find a TernD71 and ride it first :-)

best Thor

fietsbob

Thing that makes the Merc lighter was the aluminum use instead of Steel , but the aluminum fatigue cracks and fails.
... as you discovered..

SJS has the main Subframe , since I see the Brommy Rear section in the picture ..

I see some SP widgets like the FD adapter bracket, in that picture, so might as well get a Brommy..

the Newer 6 speed use a hub the BWR that was designed by/for Brompton, made by the new SA sun-race company..

the older 6 speed was adapted from an Adapted Sachs 3 speed hub..

But thankfully they used a thinner 13 & 15 t 3 spline cog , which works on the older AW3 & BSR hubs too.

so you can use 3/32", 5678 speed derailleur chain . for better shifting with the double chainring set-up.

newer BWR uses a 9 spline 13,15 cog, .. as does the 2 speed hub.. 12, 16t..

EvilV

Thanks Thor. I know you know those Terns from your business. I don't need to take the bike on trains or public transport, so the less neat fold of the Tern would not be a deal breaker at all. I want a durable bike with an internal hub that isn't inefficient, and a good ride. My terrible old Merc still rides rather nicely on the footpath I use it on for leisure and exercise riding. I have little or no chance of finding a Tern D7i up here where I live. It isn't the kind of town where people commute on folders. They are as rare as hen's teeth up here in Newcastle upon Tyne. There are plenty of bicycle commuters, but they use full size bikes. I could check for dealerships which sell Terns, but I doubt I will find one within a couple of hundred miles.

Reading the reviews (which I have) the D7i rides well and is probably robust enough for me not to break it.

EvilV

Thanks for the info about the new Brompton six gear hub Fietsbob. I had no idea that was how they are doing it now. I thought it was still achieved with the two speed derailier like before. Neat idea.

One thing that concerns me slightly about the Brompton - although an iconic folder and beautifully done is the chain tensioner thingy. I had a bit of bother with the fake B when the tensioners broke. I went through three of those things until I got a metal one, and I twisted the little axel on one of the jockey wheels on that when I was hammering along and somehow the chain snagged and bent the bugger. It was easily fixed with a new bolt, but I kind of feel that the Tern fold which doesn't interfere with the chain might be a better engineering arrangement. As I said, I won't be carrying it on and off trains or buses every day - if ever is the reality. It will go in the car boot folded and that is about all. Mostly it will stand in my hallway and be wheeled out to run around the old wagon way I ride on, or to spin around to the shops or to visit a mate's place. People might ask 'Why have a folder then?' The answer is the versatility of dropping it in the back of the car and the ability for it to stand inside my hallway without being a nuisance by taking up space.

badmother

Welcome back.

I have not seen a Merc apart from on pictures, but is ist possible to buy a new main frame from SJS and use fork and rear triangle from your Merc? You could go to a 5, 7 or 8 speed hub if you wanted instead of the B gearing system.

EvilV

Hi badmother. Nice to see you again.

I had thought about that and looked into the prices of SJS frames for the B the other day. They came out at something like £350 which seemed a bit outrageous to me, but then I am a cheap skate and rogue.

I think the Merc bits would fit, but I I'm not certain. I have a stack of spare parts brand new for the Merc. I got a ton of stuff from Little Pixel when he did away with the frame on a Brompton and built a special by using the Merc frame and the Brompton parts so it likely is possible to do it the other way around. I have spare chain rings, brand new fenders and rack, spare rear frame, brand new rear wheel and SA Sunrace 3 gear hub, spare brake levers, cables, two unused tyres and some tubes.... The ideal would be to get hold of a second hand frame for a B. There is a so called 'Project Bike' on sale on ebay which is an old Brommie. I wondered if it might be a knocked off one. They are stolen pretty often in London by the local villains.

fietsbob

I have an M3L just upgraded the chain tensioner pulleys to TacX sealed bearing nylon , from the original hard plastic ones...
in the hilly west I bough a Swiss Mountain Drive Crankset, to double [2.5] the range, downward .. (54:15)



Now the 2 speed scheme as it uses a custom Pulley with flanges on either side , that cannot be changed
as the whole thing is pushed sideways in switching cogs..

On this side of the pond, Bike Friday Tikit has different approaches..
1) their season Tikit tensions the chain directly..at the rear dropout + the fold is ahead of the BB shell

this also makes the belt drive option possible .. Shimano Nexus 8 speeds, are one option from them

they are built from raw materials,. in sizes, when ordered. JIT, mostly ,

rather than racked up in various colored component parts, then assembled when ordered.

As the factory pictures taken at Brompton works, suggest ..

BruceMetras

The Evil one is back! Nice! .. the knock through the years on the Nexus Inter7 has been weight (hefty) and efficiency (lack of) .. I'd peruse the web for articles on the Nexus 7 before making a buying decision.. the good news, if you went with a D7i, and you didn't like the hub, you could always do the Mulleady thing, lighten the wallet, and toss in an Alfine 11 ..

EvilV

I'm working through some of the articles about the Nexus 7. So far it seems to have well spaced ratios and reasonable reliability, if at the cost of frequent re-greasing service. I've found no actual figures about efficiency, although it will obviously suffer penalties like all the multi gear hubs that have more than one set of planetary gears. The single planetary designs like the SA AW that I am familiar with, also suffer some efficiency penalty, but it is slight. On my own folder, I am mostly riding in the direct drive gear with a sixty inch ratio, or paying a small penalty with the eighty inch top gear, or the 45 inch bottom one. Maybe I am kidding myself and putting a fair bit of effort in that never gets out of the hub.... Not sure really. I am much faster on my slick, high pressure tyred, derailier mountain bike.

More reading to do here.

EvilV

I think I misunderstood this post where you talk about the new Brompton six gear arrangement. I thought you meant it was a new hub with six ratios on it, but on reading stuff on the web, it seems to be a wide ratio three speed with the same old two cog system swapped by a derailier. That is a hell of a lot less attractive than what I thought you had said and my earlier comments about efficiency must have looked mad.

I can never see why Brompton don't work with a double chain set and front changer like Steve Parry does for people. I have one of his brackets on the Merc and it works great with a really cheap front changer and an extra chain wheel. I have the big chain wheel on the outside of the spider where the old aluminium chain guard used to be and the small ring on the inside where the old 53 tooth wheel was. I am running 53/45 on the chain rings and I get 33 inches to 80 as far as I can remember.

I went on the Build Your Own Brompton pages of the B website and put together my ideal B. Six gears, fenders, M type, Raw Laquer, Shimano dynamo and lights..... Comes out at over £1100..... That's a mad price - just mad. I know a guy who is running around in a tidy little car that he just bought for £250. I need to get a ride on a Tern D7i and see what I think of it, but I don't know any dealers around these parts.

fietsbob

The Sachs hub was a little closer to the AW3 in ratios , the new BSR hot wider spaces so the half step works better ..

https://www.sturmey-archer.com/products/hubs/cid/4/id/64.html its a 5 speed
2nd planetary set, around the 3 in the regular .75,1,1.33..
adds a 0.63 and a 1.6X .. narrow so will fit in the Brompton Frame
I think SJS has the core so you wont have to rebuild the wheel , just unscrew the driver from the shell.


Florian Schlumpf makes a special version of the Mountain Drive torque stop sits on tol of the bottom shelf on the frame.
behind the BB

The 3 speed hub gets run through twice .. double shift at 4~3..



using the 5 speed the .63 in high range is = to the 1.6 in low range .. so gain ia one higher and one way lower

other one. Speed drive 1.6 overdrive , 34t acts like a 54.4 when engaged.

I figured with the 5 speed hub a 13 : 39 , would do for my around town trips 3rd to 6th with my current MD54t /BSR 15T set.

but the heel tap and lever on the bar flick is easy enough.. better than the AW3 trigger was..

I have a similar Bolt on Derailleur mount I Got through Fold-a- Bikes . never went through with it..
the double planetary shift is so much better functionally ..

Id sell My FD bracket, a New Bz on FD and the lever and cable for a $C note.


Over there; note this Option: https://www.kinetics-online.co.uk/fol...n-8-speed-kit/

You might even go for his Rohloff Hub modified rear section

I have a R'off Bike Friday . has become my Rain Bike ,

just cannot stow it under the table in the Pub

badmother

You`ll give him a heart atack with your suggestions

fietsbob

The 'Brompton Should' crowd does have other Options .. the Company sells every one they make .

There, seems to be a lot of aftermarket modifiers over there , they just make the changes they need..



'You Guys Should' is not even passive-agressive ..

badmother

Found this mod recently. Been thinking of this myself: https://www.foldingbikeguide.co.uk/re...eed-conversion But I think I decided against a solution with two shifters and cables.

Here is another one. Not sure why they want 16 gears (and the weight that comes with it) but sounds like they think they need it: https://mistymornings.net/blogs/mm/?p=27

Been eying the different Shimano hubs but tink that at lest 0,5 kg extra for the 7 or 8 is more than I want, especially with almost the same range for the 7 speed Shimano and 5 speed SA.

If I do a change this autumn I am going with the SA 5 speed. I already have a SA StAr5 w two wires but I hate to travel with a bike with a unprotected togglechain sticking out on one side plus the tall nut.

What I REALLY want is a Nexus5. I do not like chains and clickboxes sticking out of bikes, especially not folders. I would like to know more about the new Nexus5 and when we can expect it.

What I was trying to say is that your suggestions to EvilV is all good but he indicated that he is not willing to spend a lot and your suggestions are NOT cheap.

fietsbob

Im only in it for the Recreation , while I listen to the Radio Over the Web

if I had something to sell , and bills to pay that way, things would be different.


BTW there are plastic covers that keep the indicator chain from getting whacked .. I have 1 on my BSR..


SA catalog; this is their internal shift https://www.sturmey-archer.com/produc...3/specs/1.html
but too wide for standard dropouts on Brompton rear ends..

Older Mk2 bikes had a left side place for another roller for the 5 speed 2nd cable ,
but the Company ran out of Hubs to ship to Brompton , so as I read, in the Book
they contacted Sachs , and the 3 by 2 scheme was the result.

bhkyte

Welcome back evilv.
Just get a mezzo mate!
I ode a dualdrive P24 a few weeks ago. £600 on line looks very strong and will carry an elephant ( maybe)

badmother

Plastics yes, I buy them and loose them.. Still stuff is sticking out, plastic or no plastic.

This is the 5 speed: https://www.sturmey-archer.com/produc...d/4/id/11.html

fietsbob

theres the roller end as well as the funnel nut type ..

Front wheel covers things up when it's folded..

this ones wide 119 version is the other High flange ones narrow version
https://www.sturmey-archer.com/produc...d/4/id/64.html

111 is the narrow .

badmother

You are right about the link, I mixed up 119 and 110. Not sure about the spline thingy since I intend to use only one sprocket in the rear- unless I do this: https://www.foldingbikeguide.co.uk/re...eed-conversion sometime this winter. I was more leaning towards a double front with "greasy finger shifting" for less weight and less tinkering.