Sprockets Can I mount a sprocket on a Shimano nexus 7spd internal hub?

Discussion in 'Transmission / Drivetrain' started by Irish John, Jul 7, 2008.

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  1. Irish John

    Irish John Guest

    I'm wanting to buy a Schwinn Deluxe Seven cos it has springer forks. It also has a Shimano Nexus 7spd internal rear hub and a coaster brake. I'm wondering if anyone knows if there will be a problem fitting the rear sprocket onto this hub? The sprockets for the HTs and Grubee Hondas are all the same when it comes to the hole in the middle and the 9 bolt holes etc regardless of the number of teeth. I'm building a Honda Grubee and will use a 50 or 52T sprocket. It's the hub I'm concerned with cos I can't see the bike til its already bought and nobody around here has a nexus 7spd for me to look at. Someone here must know about these hubs I'm sure.

  2. loquin

    loquin Active Member

    First off, the grubee 4-stroke is NOT a Honda. And, despite what the e-bay vendors claim, I've never seen any proof that Honda had anything to do with the design.

    Second. Those sprockets clamp to the spokes, so there shouldn't be an issue in clamping them.

    Third. Does that bike have front brakes? Because you REALLY don't want to be riding it without front and rear brakes. It just isn't safe.
    Last edited: Jul 7, 2008
  3. sjackson

    sjackson Member

    I think his question was if the rear hub was too big to fit the sprocket over... which it might just be. But don't take my word for it. I can't find any specs on shimano's website... sorry.
  4. MasterLink

    MasterLink Member

    my Honda is a Honda its stamped in the case clear as day ..its a great motor 1/2 pull runs smooth ...

    john you will have to find out how meny spokes and you might have to make the hole biger on the sproket here is a post talking about it http://www.motoredbikes.com/showthread.php?t=11649

    john i just talked to jermey at http://www.bicycle-engines.com/brake-heavyduty-axle-p-141.html
    and will have these soon looks very nice as you could change the sprokkeet out fast i have bent spokes now dont want anymore this will help
    find it there also so u can see how it works
    i will be getting out my jag also as its a hard tail and after the 12 mph 7spd.the gears are useless:rolleyes:
  5. Irish John

    Irish John Guest

    Loquin, My question was basically about one thing - can I get the sprocket to go over that hub? It will be a Honda with Grubee gearbox. Of course Honda have nothing to do with the Grubee gearbox - that is obvious to blind Feddy. I know you need a 36 spoke hub for the best clamping. I've fitted dozens of these things on wheels but never on the Shimano 7spd hub.
    No the bike hasn't got front brakes and yes it will have when I've finished with it but my thread is about the hub. I've another thread somewhere about springer forks.
    There's a flange on the hub which looks problematical and if I enlarge the centre hole so it fits I reckon the 9 other holes could be impeded by the flange and could also need to be redrilled and if that is the case the Deluxe Seven will stay in the shop unpurchased because it is also $375 dearer than the Alloy Seven and that is just how it is in Australia. Some models double in price for reasons best known to the sole importer.
    Someone on this forum will know all about this hub and I'm sure I'll find out what I need to know.
  6. Irish John

    Irish John Guest

    Thanks Masterlink, I think you are referring to their freewheel rear sprocket option which I am not interested in because it's too expensive for me to rebuild a whole wheel. That 7 speed hub and coaster brake is worth $400 and I wouldn't want to not use it. The freewheel rear hub is OK but I don't think it can be integrated with the Shimano Nexus 7. Also it's Chinese. I'm happy with just the front freewheel drive sprocket but I suspect the sprocket wouldn't fit over the hub and the hub flange would get in the way of the bolt holes. Jemma UK has this bike and she might know the answer to my query. If there's a problem with the hub I'd use another Alloy Seven cruiser which is problem free except it can't take springer forks cos the head tube is longer than any springers on the market. No front suspension is a problem I find and the motor tray takes a beating on the bumps with rigid forks. Here's what the hub looks like. The one with a black arm coming off it is a roller brake and the one with the long silver steel arm is, I think, a coaster but I'm not certain about that. They are both Shimano Nexus 7s.

    Attached Files:

  7. MasterLink

    MasterLink Member

    yes i was talking about that ...i see what you mean ...you could alway call him over there and ask ..and i know what you mean about the bottom plate i put a 2x4 painted it black under the back part of that plate... and a clamp under the front it holds nice now ..iam not happy with the bike i have put lots of miles on it and my front 11 tooth free wheel was lose i found out why it was missing ball bearings the two races got lose some how new one is ordered and on its way .
    iam looking to get that k2 easy street heres a link talking about it i like that it has the seat post and 1/8 inch head tube but iam still not sure why you would like 7 gears i just use 1st gear i would peddle with the motor i guess if i had a gear that was low enough my bike hates to go slow over 20 its ok
  8. Irish John

    Irish John Guest

    Re wanting a 7 speed hub the answer is I don't want it but it comes with the bike and at $400 per hub I'm too tight-fisted not to use it. I just want a Schwinn with springers but not a Walmart type Schwinn. I dislike coaster brakes with a vengeance and I thought they came in with bubble gum and puberty and would have died out of fashion years ago but there they are hanging around for decades like rap music.
    That's not good about losing the ball bearings from your 11T freewheel. I'l check mine to see but I think it's all OK. I'm pleased with my HuaSheng and Grubee but the kill switch was rubbish and the chain and the pet cock which snapped on day 10. All the fixing bolts I never used cos I knew about them but I really dislike how they use threaded bolts into aluminium on the tray. Those things really annoy me. At least the motor is good and the 11T has been great too. I use really top line 415 chains - those extreme BMX ones and they are kinder to the sprockets cos the links are all the same length which the supplied chains aren't.
    I agree with you that all I need is about 4 gears and I'd love a 56T chain ring on the pedals so I can cycle along merrily at 28 mph. I think the NuVinci would be fantastic if we could only use it like the Staton rigs. The new Schwinn is not for me but for a person who wants me to build it.
    The bike I would kill for is a Felt Heritage cruiser which can't be bought here or even a Felt MP. Now I mention it there's a thread here about a Felt MP build and that has a 7 speed hub but only the Aussie version has the 7 speed I think and they cost $1200 here maybe more.
  9. HoughMade

    HoughMade Guest

    Grubee designed only the gearbox, not the engine. The engine may be either a Honda or one of a few "clones" of the Honda. I use a Honda engine with the Grubee gearbox. How do I know? The "Honda" cast into the side of the block and all those Honda stickers were my first clues...and the fact I bought it from a very reputable small engine dealer in my home state.
  10. ocscully

    ocscully Member

    Nexus Measurements

    Photo #1 shows the Shimano Hexus Hub these measurements are taken from. Photo #2 starting from the left side of the photo the black straight shoulder of the hub is 53mm dia., at the smaller edge of the silver 65mm dia., at the shoulder where the taper meets the hub flange 74mm dia., OD of the hub flange 105mm

    The first photo above in post #6 of the two nexus hubs I believe is of a 4-speed with a steel hub body.


    Attached Files:

    Last edited: Jul 9, 2008
  11. gno323

    gno323 New Member

    yes I did it to a 3 speed, I had to get the sproke Inside diameter widened, and on the HUB I had to dremel a few holes so the screws would go through. I think it works better. Do to the fact that the sproket is now connected to the hub rather than the spokes.
  12. gno323

    gno323 New Member

    mine is like the first picture, electra relic cruiser
  13. JemmaUK

    JemmaUK Guest

    Thats the later cyber-nexus 4 I think which bears no relation to the 7-speed hub at all. On that there is no double shouldering and its a 36-spoke wheel. the size of the hub at the point where you would mount a sprocket is approx 2cms

    Jemma xx
  14. ocscully

    ocscully Member

    Below are photos of the Nexus Inter-7 Coaster hub on the left and the Nexus Inter-8 Coaster hub on the right. The measurements in post #10 are from the Inter-8 Coaster hub but as you can see the Inter-7 Coaster is very similar. The Inter-8 has a slightly larger dia spoke flange 105mm vs 100mm for the Inter-7

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    Last edited: Jul 9, 2008
  15. Irish John

    Irish John Guest

    Dimensions of Sprocket Holes

    Here is the dimensions for a typical rear drive sprocket in case anyone has one of these Shimano Nexus 7 spd hubs. The hole is 37mm dia. and the distance from centre of hole to edge of bolt hole is 33mm. The dimensions are the same on all the sprockets I've seen.

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