Rover I8 Questions about adding a 2 or 3 cog crankset.

edited November 2017 in Rover
Has anyone out there changed the rover to a 2 or 3 cog crankset? If so where did you mount the derailers? Is this feasible with the internal 8 hub or will I need to swap out the rear wheel and gears? Please reply with pictures so I can show the bike mechanic it can be done. He also told me the frame where the rear wheel mounts does not have enough room to change out to a different wheel with gearing. I do go up hills in 4th gear currently. How much will this effect uphill climbing?


  • The issue with adding a 2/3 crankset is finding the correct mounting post for the derailleur. A number of members here have done the mod and I'm sure will provide their information regarding parts and placement. Good luck.
  • I have done the front derailleur post, front derailleuer, double crankset, front shifter mod. And if you do that with an I8 rear wheel you are going to need something to take up the chain tension. For me I like older tech bike parts and have an x8 rear wheel. I would suggest instead looking into the Patterson 2 speed front crankset. I have no experience with this device but there a lot of members here that have it and can tell you what you need by your riding requirements and how much it costs. I am guessing the cost factor will end up about the same either way you choose.
  • If you want to go a bit higher in the price range, you could also look at other Internally Geared Cranks. There is the Schlumpf Mountain Drive, which gives a 2.5:1 down. (Giving a 32T crank down to an 13T. Effective if you want to go sub-10GI.) There is the Speed Drive, which gives 1.6:1 UP, turning a 32T into a 51T. And then there is the High Speed Drive with its massive 2.5:1 up. This effectively turns a 27T into a 68T and makes it easy to raise the GI range over 100 for those so interested.

    Each of these options is, well, fairly expensive at roughly $700 for any of them. BUT, they are solidly built, virtually problem free and silent as all get out. They can be used with or without doubles or triples so the needs for a chain tensioner is non-existent for the single sprocket versions. Custom chain rings are available from a wide range of sources, and all three can use either a 100 spider or a 130 spider, giving the largest range of gearing options in a single package.

    There isn't a need for a derailleur post, as shifting is done by clicking buttons in the center of the crank spindle with your heels. Button in one way, normal 1:1. Button the other way and either you're geared up or geared down. (Depends on the model.) Clicking the button over is intuitive after a couple hours of riding and becomes second nature fairly quickly.

    While these are a high priced option, they each provide options that can't be gained in any other crank set. (Gearing up a 52T front with a Speed Drive still means you are well into a 80T+ front crank for you speed demons out there!) Doing an HSD with the stock 27T gives a 68T, but if you go with a double or triple, you could easily hit 100T+ meaning over 120GI. Not many of us here could turn that at 20RPM, let alone 60-90RPM...

    And to get sub-10GI range with any other crank set is going to be hard to do without using a MD. (Easy enough to do with a 28T front and kicked to low on the crank. (9.5GI for a single speed rear and a 22T sprocket. Almost impossible to get anything that low on a single speed hub!) With a Nexus-8 and a 28T on the front can get as low as 5GI with a 20" wheel and a 22T sprocket. With gearing this low you could almost walk a trike up a wall... :)

    These aren't for everyone, but for those that take the plunge, they are an example of exemplary German engineering.

  • edited November 2017
    I bought a derailluer hanger from TT (designed for Rover) and hung the cheapest derailluer I could find. I did have to replace the high limit screw on it with a longer one in order to get it inline with the single sprocket of the SA i8. Also buy one box of KMC-Z72 chain from Amazon (around $6) because you'll need to add about 10" of chain to handle the larger front sprocket as well as the rear derailluer in's and out's. Each box comes with a master link. Essentially, when you are in the lowest ring, you want the chain as it goes from the top roller to bottom roller in the rear derailluer to be almost (but not completely) horizontal. Make sure there's tension, even though it's the smallest ring.

    As for the front crankset, I got a Sunrace 22/32/42 from Amazon. Also bought a front post from sales AT (ask for the updated 66 deg angle one - it can handle both MTB and Road derailluers) for about $40, a Origin8 cable stop hanger from Amazon, and finally an E-Type front derailluer for $50 from Jensonusa. You can just buy a regular one to hang it on the post if you want. The E-Type mounts to the BB. Also, the poweroncycling post may need to have the built-in cable stop ground down, as it gets in the way of SOME derailluer's movement. Plus make sure the front derailluer you buy is intended for the size of rings on the crankset you buy (i.e. max 44T, 20T max diff small to big, that kind of thing).

    As for shifter, pick whatever you want. I did a trigger shifter, but now that I'm having some carpal tunnel issues, I wish I hadn't.
  • a shimano hub with a patterson 36-tooth crankset will put rover at 22-107 gear-inches for $350 + install cost. pix of derailleur installs, search on terratrike rover x5.

  • Thanks everyone! I have another question for you that have done the modification. Are you happy with this or would you not recommend it?
  • I'm happy. It's stable and works well, and I think the last time I checked the sheldon GI calculator I was around 13GI on the low end. Mind you, there was a terrible learning curve and I probably spent more than necessary, and I miss having a straight chain with no derailleur (I worry about the rear derailleur getting bent on something I run over, as it hangs within 1.5" of the ground in high gear).

    When all is said and done, though, I'm happy because I have the range I wanted and I don't have to worry about my knees so much on hills. On flats and downhills I'm able to maintain my spin rate without overspin (unless it's a steep downhill) and increase my avg speed at least 1mph.
  • I set up my trike to match my ex Tour Easy. My Tour Easy had a triple crank but I used the middle chaining 98% of the time. I expect to use the small 40 tooth chaining a similar 98% of the time on the trike.
    Weldin4. What kind of riding do you expect to do? Lots of hill climbing? Lot of flat terain riding? Medical restrictions?
  • edited November 2017
    jrobiso2 says it well.

    probably best to discover the gearing that would make you happy before settling on how to accomplish. a testride on any trike with a triple up front could point the direction.

    i swapped driveline components between rambler and rover [used a MoonTimber derailleur post]. a triple on the rover did the same thing as a patterson with nexus-8 on the rambler. my case, a better chainline with the nexus combo made me happier.

    but, if i had the engine for cruising, would use a derailleur setup. for climbing serious hills, would be the nexus hub. if interested in physical training, would have gone with a nuvinci hub and patterson crankset.

    at the moment, being somewhat decrepit and a sidewalk rider hauling groceries, a 7-speed derailleur makes me happy enough.

  • edited December 2017
    mrbill5 My main goal is to have the option to go faster with the 20 mile bike events. I know I won't keep up with the bikes just not as far behind them as with the standard 8 speed. My main daily rides are currently flat with a modest hill or two. I try to get 12-20 miles daily. One hill currently requires me to drop in the 3rd and 4th gear on the 8 speed. I just want the option to go faster than I can with the 8 speed when I want. Probably 5 - 6 20 mile bike events in the year. The last Saturday each month recumbent rides not that big of a issue with the speed. I'm in my mid fifties probably 20lbs overweight. Just got back into triking in August. Fairly in good shape currently with Afib heart issues that I've had over the last 20 years. My doctor tells my to bike to my hearts content! I know what my personal limits are and do not to exceed them as far a stressing the body.
  • If you are spending all your time in 7th and 8th gear when on the flats, then yes, a larger ring MIGHT help you gain speed (so long as you can maintain your spin rate with larger gearing). A larger crank ring on a trike is not a magic bullet - you won't suddenly become a 20mph avg speed monster.

    I think @jamesr would agree that it's always the engine - you. If you are spinning out in 8th in your IGH, then ok, go higher. If you only have to go down to 3 or 4 going uphill, then you likely don't need smaller rings up front.

    Perhaps go for a 2-ring setup, the smallest matching your current ring and one larger one, but again, it all depends on the engine.
  • Yea I'm mainly in 8th gear all the time. Thanks for the help!
  • First pass I would put a slightly larger chaining on it, say 2 to 4 more teeth. About $20 if you shop around. You may need to add a link or 2 to the chain unless you have enough horizontal travel left on the rear wheel dropout.

    More involved is a double front crank. Ebay double crank, $20 to $100. Front derailleur $10 to $20. Front derailleur post $45. Front shifter and cable $20 to $40. Plus tension device if you have an I8 rear hub.

    Or the Patterson 2 speed front bottom bracket.

    Or, just to give you another option since you are still a rider in better shape than most of us you could go the 24 or 26" rear wheel route. TT sells 26" wheels. You would transfer the rear cassette to the larger wheel and have a huge number of 26" rear tires and not so many 24" tires to choose from. Be aware that raising the rear wheel brings the bottom bracket down about an inch. If you have large feet it could cause issues with road heel strike. To get a rough idea if you want to do this put the rear wheel on a piece 2x4 wood and back pedal. Not the same thing as actually riding but it will give you an idea of the layout.
    Do you have access to a 26" wheel either from old bike or neighbor or ???

    Oh if only I was only 20 pounds overweight........

  • If you have a standard I8 Rover then the gear range with different rear wheels
    20" 20 to 62
    24" 24 to 74
    26" 26 to 81
  • Or Keep it all internal and put a $500 Efneo GTRO (all enclosed triple) up front. Clean, maintenance free, and reliable... but a bit pricey.
  • I would prefer a 24" wheel does anyone know where I can get one though?

    I'll look into the Efneo GTRO it's about $200 less than the Schlumpf. I like the way schlumpf shifts with the center pin. Does the Efneo do that? Does it require a trigger shifter?

    I see where TerraTrike offers a Schlumpf drive thru Amazon. No specifications on ratios. Does anyone know the ratios offered through Terra Trike? Couldn't I just directly order from Terra Trike or is this a deal where I have to go thru Amazon?
  • weldin4 wrote: »
    I would prefer a 24" wheel does anyone know where I can get one though?

    I'll look into the Efneo GTRO it's about $200 less than the Schlumpf. I like the way schlumpf shifts with the center pin. Does the Efneo do that? Does it require a trigger shifter?

    I see where TerraTrike offers a Schlumpf drive thru Amazon. No specifications on ratios. Does anyone know the ratios offered through Terra Trike? Couldn't I just directly order from Terra Trike or is this a deal where I have to go thru Amazon?

    They sell a set of 3, 2 front and one rear. They probably would sell just a rear to you since they sell just 26" ones as an $100 option. Email em.
  • But, when you buy them, you still have to pay someone to mount the rear axel in the rear wheel. I don't know how the front brakes attach but they would have to be adjusted also.
  • Rear axel would involve either moving the rear cassette from the 20" wheel or putting on a new one. And transferring the quick release from the 20" wheel. Plus tweeking the rear derailleur. However an I8 rear hub/wheel would have to be sourced elsewhere. That is not my area of expertice. Perhaps Utah Trikes could put one together with a gearhub, 24" rim, ss spokes. Probably suggest a 24" tire or two.
  • The Efneo GTRO ($500) is an internal triple gearbox that shifts via a thumb and finger handlebar shifter that typically is placed on the opposite handlebar side from the hub/dérailleur shifter. It comes in a standard size so you simply remove the pedals, arms, and stem, and simply install the GTRO. The shifter and everything else needed comes in the box.

    The Schlumph, an internal double gearbox, requires some modification to your bottom bracket before it can be installed. I'm not sure if this can be undone so that you could replace later what you remove before the bottom bracket alteration... I doubt it though. If it can be removed and a normal bottom bracket can be installed, I may have a used Schlumpf I might sell you. Because I would 3 times the gears as my trike has rather than 2 times the number of gears.

    If your goal is to easily get over 100 gear inches, it will be easier to do with the Efneo, and additionally, you'll have more gear options between the low & high extremes or your gear inch range.

    But before you do any of this I strongly recommend you try to find a trike that has 90 gear inches or more, and see if you can ride on level terrain at a cadence (pedal rpm) of at least 75 and preferably closer to 90. If you can't, you are probably waisting your money on trying to get a gear inch over 100. Riding hard at lower cadence is a recipe for blowing out a knee and/or hip.

    Can you currently pedal at a cadence of 90 in your highest gear and maintain that speed for a mile or more? I doubt many on this forum can do so. I ride nearly everyday, and my top gear inch (i8 Nexus Rover) is 62. I could hit a cadence of 90 in 8th gear, but I can only hold there for maybe 1/4 mile. I have heard a few riders over age 50 claim to be able to so ride, but none have yet succeeded to prove they could maintain that cadence for a mile. It's fairly easy to cruse at a slow cadence in a high gear which initially made me believe that I could easily maintain a high cadence in 8th gear.

    Before you spend money giving you a top gear inch over 100, make sure it is going to actually get you the kind of speed you are looking for. I believe your money would be better spent on an electric assist motor & battery. You can use the assist when you want, or simply ride without it. Personally, I have always favored crank-set motors (aka mid-drive - basically replaces your pedal system) over hub motors, and with the possible exception of TerraTrikes new Falco electric assist hub setup, I still feel that way.

    In case you or anyone reading this is interested, here is a link to 22 Mid Drive Kits for DIY Electric Bikes. Most everyone on this Forum who has put an electric assist crank motor has installed a Bafang BBSxx (xx refers to several motor size/power options). And probably most bought theirs through Luna Cycle online.

    Best of luck with your decisions.
  • Only time I could do 100 gi was downhill. 52 crank, 12 rear, 26" rear tire. 80gi was a stretch any other time. 40 crank, 12 rear, 26" tire. If you can do 100gi well god bless your good knees.
  • GI's like that are for DF bikes!
  • The Schlumpf drives require a chamfer on the BB in order to work correctly. This isn't a deep chamfer, but one that takes about half of the thickness of the BB's shell width. There is a tool that Schlumpf makes and sells (as well as rents) for putting this chamfer on. Rental is something like $70. (Ideally a shop would line up 4 or 5 installs and do them all at one time, then return the tool.)

    Putting the original cranks back in is as simple as removing the Schlumpf and replacing with the original crank. The hardest part is removing the Schlumpf's crank arms, since the shifting pin is in the middle and needs to be protected or it will bend.

    The HSD's 2 speeds have only 2 over-lapping gears on my Nexus-8. 7L is about the same GI range as 1H, and 8L is about the same as 2H. Shifting can be done on the fly with just a heel flick one way or the other. So for my 16 available speeds, I have 14 different gears to use, instead of 10 as most 16 speed arrangements would have. With GI ranges of 12" to 96" all available with a heel click and wrist flick it's pretty easy to find a GI for the conditions and cadence I want to ride with. (22T on the Nexus and 27T on the Schlumpf, so I'll let others run that through a gear calculator.)

    My HSD has a 27T on it, which is the stock chain ring for the model. Kicked over to H that 27T turns into a 68T. To put 2 chain rings on it is a simple matter of replacing the 27T with a 110 or 130 BCD spider and putting in the chain rings you want. It's easy to get into the 120"+ range if you really want to. (a 52T chain ring kicked to high is something like 130T when in high. Again, I'll let you run this through a gear calc.)

    As far as having 100GI or more on a trike.... If you can push it, then it doesn't matter if it's on a DF or a trike, does it? We're not all in the same physical condition, and some of us might be able to do a lot more than the others. As @mrbill5 said, if you can push it, you got good knees! :)
  • ...not just knees, you got good everything!
  • How about keeping it a 38T single crank?
  • Well I found an internal FSA Paterson crankset For $226. I could not pass it up. Its being installed today. I think this is exactly what I'm looking for.
  • Good choice. Give your impressions after living with it for awhile. Knowledge is power.
  • think you will like your decision. the basic patterson-nexus combo will raise your top end at 60 rpm from 11 to 15 mph.

    if you have the engine and no hill worries, the optional $50 36-tooth patterson chain ring can move you up to 19 mph@60 rpm.
  • James is it the same with the Sturmey Archer 8?
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