Review: Dynamic "Crosstown 7" Shaft-Drive Bicycle

Review: Dynamic “Crosstown 7″ Shaft-Drive Bicycle

July 26th, 2007 by Jack "Ghost Rider" Sweeney · 17 Comments

Dynamic Crosstown 7
The good folks at Dynamic Bicycles offered their “Crosstown 7″ commuter bike to us for testing. In many respects, it is like so many other commuter-oriented bicycles on the market — TIG-welded aluminum frame, mounting points for fenders and rear rack, upright riding position. Where this bike differs, however, is how power gets from the pedals to the rear hub. This bike uses a very clever and deceptively simple shaft-drive. Yeah, that’s right — no greasy chain, no chainrings to chew up your pants. In fact, Dynamic takes things a step further by mounting the shaft-drive to a Shimano Nexus Inter-7 internal hub. So, no derailleurs either!

The heart of the Dynamic drivetrain — the shaft-drive assembly:

Here’s some of the specs, straight from the manufacturer’s website:

The frame for this bike is unique: a narrower-width bottom bracket (BB) shell that is also larger in diameter from a traditional BB and elevated chainstays that are welded to the base of the seat tube rather than to the back of the BB shell. The elevated chainstays give room to mount the shaft-drive assembly. The rear-facing “track style�? forkends position the rear wheel in the frame and align the rear hub’s spiral bevel gear with the rest of the shaft-drive assembly. Obviously, retrofitting this shaft-drive assembly to a traditional bicycle frame is out of the question.

Details of the unique frame:
Elevated chainstays and big, narrow BB

Bottom bracket clearance to the ground with 700×35C tires is a whopping 10 inches! And this is pure clearance, too – there is no chainring to catch on obstacles if a rider should happen to find him- or herself hopping over a steep curb.

Did I mention the paint job on this bike? In low light, it appears to be a dull charcoal grey. In sunlight, however, it shines with pink and blue iridescence…every bit as flashy and sexy as a Japanese keirin bike! For folks who like to keep their bikes on the down-low, the frame decals are applied OVER the clearcoat and are easily removable.
Here’s a picture of the headtube and the glossy paintjob…the photo doesn’t do this color justice!

The frame feels stiff…jarringly so. To be fair, this is the first aluminum-framed bike I’ve ridden more than a couple miles – I don’t know if aluminum bikes always transmit this amount of shock. The Dynamic frame appears utterly flex-free, and with the beefy, ovalized down tube, aluminum forks and 36-spoked deep profile rims, the ride felt harsh. Over two miles of my round-trip commute is over cobblestones, and it was pretty punishing! Perhaps a carbon fork and a suspension seatpost would have improved the “seat feel�? of this bike and taken some of the edge off?

The parts specifications for this bike have high and low points. Tektro Quartz linear pull brakes are about the best “off-brand�? V brakes money can buy; easy to adjust and tremendous stopping power. The Nexus hub is superlative – smooth and easy to shift and virtually maintenance-free. The front hub is a sealed bearing model made by Access. I am unfamiliar with the brand, but the hub is beefy and smooth, and comes disc-ready (Dynamic offers a front-disc brake upgrade for an additional $60). The Alex DA-16 rims are tough – real pothole killers! The handlebars and stem are workmanlike…nothing fancy. The saddle and pedals? Well, they suck. Saddles are such a personal choice that I wholly expected this “Velo Plush�? saddle to be a pain in the ass, and I was right! Also, the pedals that come with the bike should immediately be scrapped in favor of something a little bigger and with more traction. Even with lugged running shoes, my feet slipped off the pedals a couple times in the dampness that is summertime Florida. Since this bike is meant for urban commuting and getting around town, BMX-style platforms would be ideal – and wouldn’t require dedicated cycling shoes.

Over the past month, I have ridden this bike over 100 miles to and from work and on a number of recreational rides. While I don’t have any way to quantify (with cold, hard numbers – this ain’t a physics lab) just how much more efficient a shaft-drive is as compared to a traditional chain-driven bicycle, I can say with confidence that this shaft-drive feels s-m-o-o-t-h. In fact, it is so smooth that it feels oddly boneless; chain-driven bikes give the rider a lot of feedback in terms of friction as the chain wraps around cogs, chainrings and derailleur pulleys. When I rode the Dynamic, the only sensation was that I could very faintly feel the bevel gears meshing against each other – in fact, the more I rode it the more I noticed it. It is DEFINITELY different-feeling than a chain-driven bike! Another perceived benefit of this shaft-drive is there is no “gear lash�? or lag when pedaling – pedaling force is instantly and seamlessly converted to forward motion. On a chain-drive bike, there is always a bit of lag as chain slack is taken up by the derailleur springs and as the freewheel/cassette pawls engage. Not so with the Crosstown 7 – you pedal and GO!!!

The rear spiral bevel gear of the shaft-drive system as attached to the Nexus hub:
Rear bevel gear attached to Nexus hub

Standing on the pedals to grunt up hills was when this system felt weirdest – and when the nearly frictionless drivetrain was most noticeable (and appreciated!). The system is silent – the only noise it makes is some occasional faint ticking in certain gears, and that can be attributed to the Nexus hub, not the shaft-drive. This bike is STEALTH all the way! Shifting is a breeze – the Nexus hub is spectacular. I found myself shifting more often because it was so easy and smooth, and I found the range of seven speeds to be more than adequate for my relatively flat commute. For people living in more hilly areas, an 8-speed Crosstown model is available from Dynamic.

How much does the shaft-drive system add in weight to a bicycle? The manufacturer claims that the system adds less than one pound as compared to a geared bicycle, and this makes sense…after all, the entire assembly consists of four chromoly spiral bevel gears, a shaft and an aluminum housing. I think most people can live with an extra pound…and for the real weight-weenies out there, a few judicious parts swaps could help lose some of that extra weight.

Maintenance is, for the most part, a non-issue with this bike. I rode this bike in two heavy Florida summer downpours with deep puddles almost up to the hubs, and I never had to worry about a rusty chain. Dynamic recommends adding a shot of grease to the drive every 600-1000 miles. The shaft-drive comes complete with a zerk-type grease gun fitting…just attach your grease gun and squirt a bit in there. The manufacturer recommends Finish Line’s Teflon grease. I couldn’t find my grease gun, so I used a 12cc syringe with a plastic “gastric tube lavage�? tip to inject 4-6cc of grease into the shaft-drive after removing the zerk fitting with a 7mm box wrench. The Nexus hub needs occasional cable adjusting, which takes all of two minutes, and the brakes could use some occasional tweaking. Is it ever that simple on a gearie?

No grease gun? No problem, especially if you know a medical professional with access to syringes:
Syringe replaces the grease gun

Are there additional steps when changing a flat rear tire? Yes, but the process only takes an extra 30 seconds from a traditional bolted-on or QR wheel. With a screwdriver, remove the two screws that hold the black plastic rear hub cover on. Slide the cover off. Pull the shifter cable sharply downwards to release it from the hub’s cable guide and detach the leaded end from the hook on the hub. Unscrew the axle nuts with a 15mm wrench, taking care to keep the unique washers on each side of the hub in proper order. Change the flat and reverse the disassembly process. Those special washers realign the hub with the tail end of the shaft-drive, so no fiddling is required to get things running smoothly again. Hell, it takes longer to write it out than to actually do it!

The “track-style” rear forkends and plastic hub cover:
The back of the bike -- hub cover

Does the shaft-drive wear out? Well, yes…eventually. Patrick Perugini, the president of Dynamic, indicated that the shaft-drive is rated for 6000 to 10000 miles (depending on frequency of greasing) before it requires replacement. And, a replacement assembly with all bearings is only $89.00, available directly from Dynamic. Now, compare that to a traditional geared bike – can you get 10000 miles out of one set of chainrings, cassette cogs and a chain? I didn’t think so! Can you replace two (or three) chainrings, 8/9/10 cogs and a chain for less than $89.00? Only if you really, really shop around!

Two gripes stand out in my mind: the first is the riding position, which is VERY upright. While this position gives the rider a commanding view of the streets, there is no place to hide once stiff headwinds come into play. As configured, the Crosstown 7 is really not suitable for long-distance fast commuting. I would love to see a drop-bar option for this bike (or would consider one of the road-bike models Dynamic makes if a more aerodynamic position is desired).

The other gripe is that while Dynamic inexpensively offers accessories such as a rear rack and fenders, at this price point I expect to see both of those included as standard features. Most similarly-equipped bikes from other manufacturers (and here I mean geared commuter bikes) come standard with rack and full-coverage fenders.

Overall, I think Dynamic has a winner with their Crosstown 7. It appears (and rides) in every way like the around-town errand, commuting and recreation bike it was meant to be, and you just can’t beat its low-maintenance features. No more greasy chain tattoos, tattered pants cuffs or dirty hands from a mid-ride tire change!

Hits:

Misses:

Visit Dynamic’s website to learn more about the shaft-drive – there is a great “FAQ�? on the site – and to see other models Dynamic manufactures.

Popularity: 38% [?]

Bike Commuter Essentials at PricePoint.com

Tags: Bikes · Gear · Reviews

17 responses so far ↓

1 Nick // Jul 26, 2007 at 6:51 pm

Wow; thorough review. This is something I’ve been honestly curious about, so it’s nice to have such a detailed account of how a shaft-drive bicycle feels.
2 Ghost Rider // Jul 26, 2007 at 7:40 pm

Thanks, Nick…the sensation IS hard to describe — weird comes to mind, but certainly not unpleasant. I guess it is the hard-wiring that 32 years of running chains has given my legs that makes it feel so alien, but smooth like a baby’s bottom!

I can also safely say that I am no longer a skeptic about shaft-drives. This baby is well-thought-out from an engineering standpoint!!
3 Priscilla // Jul 26, 2007 at 9:47 pm

Wow. Great review! I was surprised to read that changing a flat on that bike would be so easy.
4 RL Policar // Jul 27, 2007 at 2:03 am

GR,

I think Nick James would agree with me that your review was a FACEMELTER! That’s Nick’s way of saying that it was really really good and thorough!
5 Ghost Rider // Jul 27, 2007 at 2:40 am

Ha ha! I was worried about getting a flat until I really read the directions…and removed the back wheel for a “dry run”. Much easier than it looks, and everything realigns itself as long as the strange washers go back in their proper places.
6 Ralph // Jul 27, 2007 at 8:17 am

I’m been riding a similar brand and style of chainless bike for commuting for over a year and love it. The maintenance and ridability are are so smooth, I’m kinda surprised that I’ve yet to see another one in this bike-friendly town of Bend, Oregon.

Great review, Jack. Although I’m fine with the saddle (course, I haven’t tried others so don’t know what I’m missing), your pedal comments were right on. Cheapy nylon pedals were very surprising and should be changed out.
7 Ghost Rider // Jul 27, 2007 at 9:11 am

Ralph, are you riding an Incline? Tell us more about your chainless experiences!

The pedals that came on this bike were alloy, “toothed” MTB pedals. Maybe they would have been better with Powergrips or toeclips, but I was horrified by how slick they were even with serrated cages!!
8 Timbeaux // Jul 27, 2007 at 2:39 pm

I’ve just ordered this bike from Dynamic. Based on your review, I had them trade the seat and pedals for a bike computer, and I’ll install a seat and pedals that I have already. I’m really looking forward to my new ride and will follow up with my impressions. I ride about 100km/week with a laptop in my backpack, so I need a solid mix of performance and comfort. I will not miss the chainring tattoos and grease stains in the back of my van…
Thanks for the review.
9 Ralph // Jul 29, 2007 at 11:09 am

Incline Cross 7:
http://www.giftaffair.com/images/products/1025_1091221543.jpg

Yep, I’m riding an Incline Cross 7. It’s similar in structure to the Dynamic bike you reviewed, but does have the front shocks. I’ve…
- changed out the pedals for some shimano combo SPD
- added a topeak rear rack and trunk bag with panniers.

I went for this bike because I was new to bike riding and was impressed by the minimal-maintenance concepts, AND the novelty of the system.

I haven’t been dissapointed. My first tire change from the fat street tires to MTB tires for winter riding was tough for me, since I have no bike mechanic experience. I was ready to bring my bike in pieces to the resident bike expert in our office. Fortunately, the moment of clarity hit the next morning and the bike was back in business. The next tire change back into a slimmer street tire this past Spring went much smoother.

I’m interested in reviews of the chainless for mountain bike use. The only thing I see as a problem with the gears is something I notice when climbing a rather steep, short hill up to my office. I’m standing on the pedals sometime and can feel/hear the bevel gears slipping.

However, the other 99% of my commute is perfect with this bike. I love being able to decide what gear I want to start with while stopped at the traffic light.
10 Tim // Aug 18, 2007 at 9:15 pm

I recently had to retire an old faithful commuter with something like 12k miles because it need about $400 worth of new drive train, wheel, hub, etc. :-[. However, that meant that it was time to check out the market and replace it with a new bike.
I looked around at several options, and I ended up choosing the Dynamic Crosstown 7 over the Bianchi Milano, Bianchi Bergamo and the Breezer Uptown. This time around, I wanted reliability, low maintenance, and a good balance of cruising speed and comfort. I was sure I wanted to get an internally geared hub. I ended choosing the Crosstown 7, a shaft-drive bike with the Shimano Nexus 7 internal hub.
I made my choice based on rides of the Bianchis at Ozone Bikes and reading the reviews of the Dynamic online. BikeCommuters.com gave a good review [url]http://www.bikecommuters.com/2007/07/26/review-dynamic-crosstown-7-shaft-drive-bicycle/[/url] on their site. Many of the people who write in to the Dynamic website are hard core year-rounders in the sticks of Maine who ride through snow and summer rain alike. I took that to be a pretty good endorsement. The shaft drive had strong appeal to me since I have long ago tired of sprocket tattoos, greasy fingers, chewed up pants legs, and expensive drive train replacements. The shaft drive has no exposed moving parts, does not need to be cleaned, and is an $89 part when and if I have to replace it. (Dynamic estimates its lifetime at about 10k miles.) How many chains, gearsets, and derailleurs have I been through on my previous bike in 12k miles? At least $300 worth… :-\ Daring to be a little different, I took the plunge.
The buying experience was good overall. Since they are fairly small volume, there are not local dealers, and my order was over the phone but the sales rep was helpful, knowledgeable, and willing to customize the order. They swapped the cheapo pedals and seat for a good cycle computer, and I added fenders, too. With the added delivery charge, the total came to about $750, delivered to the door. Their website estimates 3-5 days delivery to Austin. I ordered late on Friday, and it took them until the following Wednesday to put it in the mail, and five [i]business[/i] days later (Monday) it arrived. From order to arrival was actually 10 days.
Assembly was straightforward: the shaft drive poses no special difficulty, and I was eager to take it for a spin. I noticed right away that the shaft drive is not silent but growls a little bit, especially right before shifts. Otherwise everything felt good.
Here are my impressions after a week’s worth of commutes (about 70 miles). In Re: the growling, it is not altogether unpleasant, and I have quickly tuned it out, but it is not IMHO the stealth bike some have made it out to be. The bevel gears and drive shaft add a very small amount of friction relative to a brand new chain, but I think this would reverse for an older chain, and I expect that the drive will get smoother with use. Already, I enjoy the lack of worry about pant cuffs, grease marks, and I rode through the rain a couple of times this week and have not at all missed needing to clean the chain and derailleurs, etc.
I love the Nexus 7 hub, and highly recommend it: the shifts are precise and instantaneous. The gearing is well suited to my commute, which is moderately hilly (mostly along Shoal Creek from Anderson to campus). Anything hillier, and I’d recommend the 8-speed, whose extra gear is at the bottom of the range, for climbing. I’m struggling to reprogram my muscle memory since its grip shift is setup in the opposite sense from a derailleur’s. I.E. twist forward to shift down and backward to shift up. I’m sure I’ll adjust to this, but I still have to think about it sometimes. Regardless, I love the ability to shift without pedaling, a [i]huge[/i] help for hill starts.
The geometry is, for me, the right compromise between being far enough forward for speed and power but upright enough not to stress my wrists and lower back (especially with a backpack; I prefer not to use a bike rack). I saw a complaint about the aluminum frame being too stiff, but I find it very comfortable and not too jarring, and I appreciate the lighter weight. In addition, the aluminum frame displays some beautifully well done MIG-welds, for those who appreciate that sort of thing.
I do have two beefs, though, that are pretty much inexcusable for a bike of this cost. First, out of the box, the front wheel had a wobble large enough to brush the front brakes. >:( I cured this with a spoke wrench and wheel alignment rig, discovering in the process that three spokes were way loose. How this got past quality control, I have no idea, but this was a disappointment. ??? The other beef is that the crank was a little loose and creaks embarrassingly when I stand on the pedals. :-[ This has been largely resolved by using clipped pedals and shoes (no switching torque direction) and a quick tightening of the crank arms, but I would expect the cranks to be appropriately seated and tightened to avoid the noises. Again, this is minor and relatively easily fixed, but with no local dealer offering a free first tuneup, and for the price I paid, I would expect it to be ready to go straight out of the box.
Overall, I’m pleased with the purchase and would characterize it with one word: smooth. I look forward to putting lots of miles on the bike. In general, the build quality and components are good (with the above noted exceptions), and the Nexus 7 really shines. The shaft drive is pretty transparent and noticeable only because of the annoyances it doesn’t give. I think I’ll appreciate it more after lots more miles when I don’t have to tune it, oil it, clean it, replace it, or hide my greasy pants legs. I hope that shaft drives become more accepted in the mainstream in the future. I think that would be well justified, especially among the bike-as-transportation community. ;D
11 Tim // Aug 19, 2007 at 12:55 pm

I just wrote my own review this bike at http://www.austincycling.org/forum-smf/index.php?topic=98.msg215#msg215
12 AngelaBridget // Jan 10, 2008 at 11:49 pm

Hola.! Feliz ano nuevo.!
13 Another Look at the Dynamic Crosstown 7 | Bike Commuters // Feb 7, 2008 at 7:53 pm

[...] so it went with the Dynamic Crosstown 7 shaft-driven bicycle that we reviewed a few months ago. I got to ride the bike for about three weeks…and in that time developed [...]
14 Keith // Apr 16, 2008 at 6:31 pm

I just got me a Dekra Urban Voyager shaft-driven bike on Monday. I’m still getting the feel of it (I haven’t ridden a bike in at least 15 years), but it feels pretty smooth to me. I can’t go very fast, but that’s probably due to not having enough room to take off without getting on the road. I did get on the road for a small distance (uphill) today (despite my bicycle not meeting the legal requirements for a bicycle on the road; namely, it doesn’t have a bell), and I wasn’t disappointed by the speed, but I freaked out when I saw a truck coming behind me.
15 antonis tsilialis // Jul 8, 2008 at 12:07 am

in this shaft drive bike ,how can the rear wheel be removed?
16 Ghost Rider // Jul 8, 2008 at 3:58 am

Antonis, that information is covered in the article above (just under the photo with the syringe).
17 dbr // Jul 11, 2008 at 2:45 pm

I have ridden my Dynamic Crossroad 8 for roughly four months and one thousand miles, mostly for commuting. In the interest of sharing my experiences with this unique bicycle I made a website http://www.geocities.com/dynamicbikereview@sbcglobal.net/

I thought there was too much information for a post here. In my experience, the shaft drive requires regular application of grease to the shaft drive gears to maintain smooth operation (this is especially true out of the box) and there are problems with the circlip that holds the bevel gear on the Shimano hub. In addition, I disagree with the components Dynamic has put on the bike as I believe their quality does not match the price tag.

With some components and accessories I have added and a regular weekly shot of grease the bike has worked well for me. I want others who might be considering buying one of these to know what I’ve gone through to make it work for me.