Brief review of the Tern Vektron P7i .. warts and all.

GSV3MiaC

Pedelecer
Jun 6, 2020
211
134
The spec for this can be viewed at https://www.ternbicycles.com/bikes/471/vektron-p7i

I got my bike from 'Bicycles by design' in Telford (OK, really in Coalport), since they were one of the few places that actually had a usable demonstrator, which I could try before parting with a 50% deposit. I bought two, since my partner thought she would like to ride along with me .. she has since decided she doesn't like cycling, so one rapidly went back to be sold via eBay.

The only deviation from the spec I have noted is that many of the videos show the RH (detachable) pedal can be clamped into the back of the (very uncomfortable) Tern seat, but this facility isn't there on my seat. Not a big issue, since the seat isn't there either - the bike now sports a Brooks 67, whicb is 1000% more comfortable already.

The bike folds fairly easily, and while heavy, I can lift it into the back of my X3 without too much trouble. Two fit fairly easily, with a sack of bubble wrap between them, and a tie down strap between the boot rail lashing points to keep them from braining the occupants if you crash stop. You do need the back seats down, although you can one in without doing so. Removing the RH pedal reduces the chances of damage, but it not actually required; dropping the seatpost probably is, unless you are so small it is already way down. Only wrinkle with folding it to make sure the steering is rotated just half a turn in the right direction, and unwound similarly afterwards - it is possible to wind the steering through about 720 degrees, which is bad for the cables and hoses. (And potentially lethal for the rider)'

The Shimano hydraulic disc brakes work a treat, and hardly squeal at all .. very impressive, no more V brakes for me! The 7 speed hub gears work as expected, but are sometimes slow to change down unless you really give them 'pedal free time' to get on with it. The shortest gear ratio is about 3m (road travel per pedal rev) which is really too high for comfort up the steepest local hills, even in turbo (or maybe I am just feeble). A good derailleur or (whisper it) Rohlhoff, would go down to ~2m or less. I personally would like lower gears .. maybe I am doing it wrong, but at my normal cadence I hit (an indicated) 20MPH without bothering the highest gears at all.

The motor is relatively quiet, but is at the puny end of the Bosch range. I live 1000 ft up in Shropshire, and even in first gear and Turbo, some of the hills are a challenge .. my round trip to the Post Office is 6 miles of riding the brakes there, and 8 miles of (mostly Turbo) back. Motor range seems to be 20-25 miles on the 400 WHr battery, although I have not actually run it right out yet - I go it down to saying '0 miles left' after 21 miles on a cold windy day, but it still had some juice left .. just as well, the hills with no power would be a walk-up job.

Top speed is not an issue - the local back roads have gravel traps (and grass) down the middle, swathes of gravel (and driftwood) at the bottom of the hills where the streams overflow, and potholes which have been growing since Cromwell was a lad .. scare the tractors in places. The bike copes OK with most of it, but the 'Big Apple' tyres (with Tannus inserts) running at about 2.0 bar (no front suspension!) don't inspire confidence on the slipery stuff.

The steering is best described as 'light' (I must be remembering part rusted headset bearings) or, less charitably, 'twitchy', when faced with poor surfaces.

This bike is really set up for commuter road, or sustrans routes. It has all the fittings you could reasonably want (bell, lights run from the main battery, lightweight ('flimsy') mudguards, chain guard, rack, kickstand, etc), although you need to add your own panniers, and mirror.

It is (the usual, for a folder) 'one size fits all', which is certainly true of the two stage telescopic seatpost. This has nearly half a meter of adjustment (48" inside leg anyone?) , but the handbars are less forgiving, with only about 6cm of extra height on tap, so at 6' 1", I find myself bent further forward than I really like. Tern tell me "Vektron P7i comes with a 320 mm Physis handlepost. The length can be upgraded to 350 mm.", but my LBS has yet to confirm and advise how many arms and legs that might cost, and an extra 30mm doesn't sound like a massive leap upwards.

The other gotcha I ran into was that there is nowhere to attach the holder for my purchased 'sold secure gold' Abus D-lock, most of the frame being non-cylindrical, and the folding mechanism scotching some of the options. So if someone wants a (seriously heavy and bulletproof, probably overkill for rural Shropshire) https://www.amazon.co.uk/gp/product/B00HN47M5C, for which I also purchased a spare 3rd Key, get in touch .. never used. D Locks are a bit of a faff to fit to small wheel folders anyway, I discover.

My only other gripe is that whoever designed the P7I (Hub Gear) model, being stuck with the Derailleur frame / dropouts, seems to have gone for the whole 'lets use the same chain and keep as much as we can' design approach, which (look at the pics!) results in a ground hugging chain tensioner. I'm not a bike engineer, but I am sure something simpler and less vulnerable should be possible, even with the 'wrong dropouts' type of frame. I have had the chain leap off the rear sprocket (and tensioner) and jam the rear wheel once already - presumably it collected up a bit of rubbish from recent hedge trimming, and 'De-railed'.

And despite the Tannus inserts I picked up my first puncture on the same outing - a thorn which would have served well as a 1950 gramophone needle (we used to use them sometimes) had gone straight thru tyre, tannus, and tube, and finding the pinhole at the roadside proved impossible, so I resorted to the 'walk home get the car' (not having the tools or technique to get the whole wheel off while sat in the hedge). The tyre selection for Big Apple replacement doesn't include Marathon Plus (or e-plus) models, unless you want studded winter tyres (and with no suspension except the balloon tyres the doesn't sounds great).

Overall - I'd give it 3.5 or 4.0 out of 5, if you need something you can stick IN the car and take to your favourite beauty spot for a ride. For lugging around London, probably a bit heavy, and for serious off roading, forget it. It also has a fairly low weight limit (105Kg iirc), so won't suit some folks, and it isn't a full up cargo carrier.

I foresee a tradeup somewhere down the road ..
 
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Amoto65

Esteemed Pedelecer
Jul 2, 2017
807
502
61
Cheshire
Seems an awful lot of money for 2 bikes that are not really liked, I always thought the Terns were pretty good bikes.
 

Raboa

Esteemed Pedelecer
Aug 12, 2014
715
273
52
Thanks for the review, can you fit a smaller chainring to get lower gears.
 

GSV3MiaC

Pedelecer
Jun 6, 2020
211
134
Seems an awful lot of money for 2 bikes that are not really liked, I always thought the Terns were pretty good bikes.
They are pretty good bikes that's why they score 3.5 or 4.0, they are just not (IMO) well suited (at least in hub gear form) to very hilly terrain and/or heavy riders. You definitely pay extra for a) the Tern name and b) the FOLDing. If you didn't need to get 2 of them into a smallish car (inside, not hung on the back) you'd have many more (lower cost) options.
 

GSV3MiaC

Pedelecer
Jun 6, 2020
211
134
Thanks for the review, can you fit a smaller chainring to get lower gears.
'Possibly', but you'd be messing with the Bosch crankset, and probably doing bad things to your warranty, and you'd have even more slack chain to tension. Sticking a larger sprocket on the back instead might be a possible/safer option, but I probably won't try it.
 

georgehenry

Esteemed Pedelecer
Nov 7, 2015
1,425
1,251
Surrey
A good bike shop will change your front chain ring to lower your gearing. Bosch probably offer chain rings in different sizes, although any quality chain ring of the right type will be fine. For a bike shop taking a link out of a chain is simple.

Getting the right gearing for your area and style of riding will transform your riding experience.

Not having low enough gearing to get up the hills you regularly ride is a pain.

This is a relatively cheap mod that will not in any way damage your bike and only enhance it.
 
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RetiredAndRolling

Pedelecer
Mar 30, 2019
53
22
RG24
Very interesting review, thank you. I fell in love with the Vektron when I started my search for an ebike. I still think it is innovative. I was looking at folders but unfortunately was too heavy for them all, Vektron included. I ended up choosing an R&M Tinker, which was compact enough to fit in the small space I needed to place it in for transporting. While the Tinker, like the Vektron is a pretty penny, it does tick many boxes. Although a compact bike it does have the CX motor and, even for a big lump like me, hills are a breeze. The ride is always solid. There’s no low hanging derailleur, as it uses in-hub Nuvinci constantly variable transmission, with good gear ratio. For anyone looking for a compact bike that will accommodate a heavy rider with ample power to tackle decent hills (E.g. cycling up the hill on the way to Portland Bill), the Tinker will fit the (large) bill. The only change I made was to fit removable pedals For ease of stowage.
 
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GSV3MiaC

Pedelecer
Jun 6, 2020
211
134
A good bike shop will change your front chain ring to lower your gearing. Bosch probably offer chain rings in different sizes, although any quality chain ring of the right type will be fine. For a bike shop taking a link out of a chain is simple.

Getting the right gearing for your area and style of riding will transform your riding experience.

Not having low enough gearing to get up the hills you regularly ride is a pain.

This is a relatively cheap mod that will not in any way damage your bike and only enhance it.

I think changing the rear sprocket is easier.. Iirc the current one is 16T, which is the smallest.. Going to 20T (23 is also possible) should help a lot, and does not require taking off the chain guard and messing with ths crankset. It also should take about 2 links of slack out of the chain.
 
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Reactions: georgehenry

AndyHoller

Finding my (electric) wheels
May 6, 2020
13
1
They are pretty good bikes that's why they score 3.5 or 4.0, they are just not (IMO) well suited (at least in hub gear form) to very hilly terrain and/or heavy riders. You definitely pay extra for a) the Tern name and b) the FOLDing. If you didn't need to get 2 of them into a smallish car (inside, not hung on the back) you'd have many more (lower cost) options.
Thanks for the review, genuinely super helpful. Things that most worried me there were lack of ability to put on Marathon Plus and the low hanging derailleur.

Any suggestions on those other options you mention? I've been looking quite seriously at the Vektron as it ticks a lot of boxes for me - I'm unusual in quite liking a smaller wheeled bike, I want something with a decent but not excessive amount of oomph (I'll be using mostly in city and on trail paths, and want something to take the sting out of hills when I'm riding for utility not exercise) and something that definitely fits a child seat and ideally has a decent amount of carrying capacity. The folding is a good bonus for me.
 

GSV3MiaC

Pedelecer
Jun 6, 2020
211
134
Thanks for the review, genuinely super helpful. Things that most worried me there were lack of ability to put on Marathon Plus and the low hanging derailleur.

Any suggestions on those other options you mention? I've been looking quite seriously at the Vektron as it ticks a lot of boxes for me - I'm unusual in quite liking a smaller wheeled bike, I want something with a decent but not excessive amount of oomph (I'll be using mostly in city and on trail paths, and want something to take the sting out of hills when I'm riding for utility not exercise) and something that definitely fits a child seat and ideally has a decent amount of carrying capacity. The folding is a good bonus for me.
You really need to decide what your priorities are and draw up some sort of want list, maybe even weight the items. If you want to carry kids then many/most folders are going to fail the weight test I think (plus folding it with a child seat on is likely an issue), but something like the Tern cargo bikes will lug any amount of stuff (even kids) up most hills. My local hills happen to be large and hilly ('>' on the OS map, not a good sign!) so really want more oomph than the Bosch 'Active Line' (or maybe just lower gears). Other things to consider are brakes (having tried hydraulic disc brakes, for a heavier machine I think they are practically a requirement, so that rules out a lot of cheaper options). Range (don't believe what they say) and price come into it too. Oh and I happen to hate Derailleurs (I also hate chains, but I couldn't find a belt drive folder which ticked all the other boxes at the moment).
 

AndyHoller

Finding my (electric) wheels
May 6, 2020
13
1
You really need to decide what your priorities are and draw up some sort of want list, maybe even weight the items. If you want to carry kids then many/most folders are going to fail the weight test I think (plus folding it with a child seat on is likely an issue), but something like the Tern cargo bikes will lug any amount of stuff (even kids) up most hills. My local hills happen to be large and hilly ('>' on the OS map, not a good sign!) so really want more oomph than the Bosch 'Active Line' (or maybe just lower gears). Other things to consider are brakes (having tried hydraulic disc brakes, for a heavier machine I think they are practically a requirement, so that rules out a lot of cheaper options). Range (don't believe what they say) and price come into it too. Oh and I happen to hate Derailleurs (I also hate chains, but I couldn't find a belt drive folder which ticked all the other boxes at the moment).
Sorry, I realised I never did reply to this! The advice and review were really helpful. I ended up hiring a Vektron for a week but took your advice and was really forensic about my priorities. Folding didn't make the cut and I've gone with an HSD instead. Much more practical for the planned child and cargo hauling, but keeps the smaller wheel and maneuverability I enjoyed in the Vektron.
Long story short, thanks for your help!
 

GSV3MiaC

Pedelecer
Jun 6, 2020
211
134
Good luck with your HSD .. I think that's what Pete (at Bicycles by Design) rides around on himself. Yes, folding comes with lots of compromises, if you don't need it, best avoided. If you do need it, then no option.

Hiring one was a good move (although finding someplace to hire one is a lock-down challenge, you may have to leave your hands at the door).
 

NSansom

Just Joined
May 16, 2022
3
0
59
Very interesting review, thank you. I fell in love with the Vektron when I started my search for an ebike. I still think it is innovative. I was looking at folders but unfortunately was too heavy for them all, Vektron included. I ended up choosing an R&M Tinker, which was compact enough to fit in the small space I needed to place it in for transporting. While the Tinker, like the Vektron is a pretty penny, it does tick many boxes. Although a compact bike it does have the CX motor and, even for a big lump like me, hills are a breeze. The ride is always solid. There’s no low hanging derailleur, as it uses in-hub Nuvinci constantly variable transmission, with good gear ratio. For anyone looking for a compact bike that will accommodate a heavy rider with ample power to tackle decent hills (E.g. cycling up the hill on the way to Portland Bill), the Tinker will fit the (large) bill. The only change I made was to fit removable pedals For ease of stowage.
Hi! I am hoping you still use this site and will see my message as I am very keen to get your view now that we're almost two years on from your post. I have been mulling Vektron vs Tinker for many weeks and struggling to make a decision between them (I have also been looking at regular size bikes that give me fewer options for city riding, which represent some of my needs). So, if you're happy to share I would love to hear your thoughts now some more time in the saddle has elapsed.
Cheers, Nigel
 

Croxden

Esteemed Pedelecer
Jan 26, 2013
2,134
1,384
North Staffs
I thought your returned bike might be the one I bought, but mine is 8 speed.
It's had little use as it's not my prime bike, but agree about the saddle.
I went out on it yesterday.