Don’t leave me home! – Tern BYB P8 folding bike review

Our beloved dog loathes when the master leaves and locks the door. “He doesn’t need me? I could lead with my sense of smell and sound, provide security. And when I’m not needed, I’ll just follow my master’s footsteps or tuck away silently in the corner.” Oh, this isn’t the animal rights column of “Dog Monthly”? Then let start by saying that the bicycle is a very handy means of transportation for a city-dweller: it could help greatly with mobility, and when combined with other ways of transport, it virtually guarantees an earlier arrival to the destination. The latest folding bike from Tern aims to be as convenient as possible, offering a very compact folded size complemented by a myriad of features to make it the least of hindrance when it’s not being ridden.

To continue the analogy, the folding bike is a particular breed within the “bike kingdom”. The engineers have a lot of technical aspects to take into account, and these have to be thoroughly reconciled to make a well-functioning folder. One of these characteristics is the wheel size, which could be a tiny as 16” or even smaller, or up to 26” on the other end of the spectrum. The former lends itself to a very compact folded size, but entails compromises in bike handling. The latter size places the emphasis on ride character, which is virtually indistinguishable from conventional bikes, but once folded, a large-wheel folder always ends up being cumbersome package.

This is all simply down to physics. As we’ve reported in our review about the two other Tern models, the brand strives to make their bikes handle like “non-folders”, ensuring plenty of stiffness, stability and comfort. Accordingly Tern refuses to employ smaller wheels than 20”, as this would necessarily compromise handling and the above-mentioned essential aspects. For the sake of comparison, many “folders” employ 14-17” wheels and out of saddle efforts are certainly a stretch on such bikes!

The advantage of a larger wheel size is straightforward, but the main objective of the new BYB model series is compact folded dimensions, where undeniably the 20” wheel size is a great hindrance from the engineering point of view. The designers at Tern had to come up with ingenious solutions in order to reconcile compact folded size with proper bike handling while also providing adequate space in the “cockpit“. The engineers certainly succeeded with the latter. The BYB defies its size when we’re in the saddle, the telescopic seat tube extends to towering heights, so even a 6’5” rider should have no problem extending the long limbs. Similarly the Andros G2 stem can be adjusted to move the handlebar in a 6” arc assuring a proper fit for virtually any rider.


Thus the wheel size of the BYB is the same as for the previous Link city folder bike series, but the similarities more or less end here. Tern has developed a complete set of technologies for the BYB to enable the success of the new folding concept. The new folding technology is called TriFold and the frame utilizes high-grade hydroform alloy paired with a double tube design. It’s a much more elaborate structure than the previous design featured on Tern bikes, the production of the so-called DoubleDeck frame likely to involve additional expense. The complex construction is in fact a necessity since there are two hinges on the frame as opposed to one on the previous design. So instead of simply folding in half the BYB folds twice, similar to an accordion. It’s reassuring that the new technology meets the most stringent EFBE and ISO 4210 testing norms, so the BYB should be safe and long-lasting.

TriFold’s hinge mechanism (TFT for short) has also been redesigned, it’s a 3D design which offers the more surface area for added stability. Thanks to the DeadBolt and SpringLock technologies opening and closing the hinge is smooth and precise. This again is not something superfluous since now there is one additional lever to operate when folding and unfolding the BYB, and the faster it can be operated, the more time is spared. Let’s also mention that the frame material is the strongest 7005 series aluminum alloy, and the new Tern Tarsus fork now has a hydroformed 6061 alloy construction.

The question to be answered is how much smaller is the folded size of the BYB compared to the previous N-Fold design? The numerous innovative ideas resulted in a 30% reduction in the overall dimension compared to the Link series, which is enough to allow the new model to fit in train standard train and bus luggage racks. But the added convenience the BYB provides doesn’t end with the folded size. The new concept carries a number of patented practical features such as the trolley wheels on the Metro Transit rack or the new closure system.

The TriFold technology is undoubtedly the greatest contributor to the reduction in folded size, but there are also some additional elements. One of these is the extra-narrow Kinetix Neutron Mini 74 front hub and the forged Tern Physis RF 3D steering pillar which holds no less than 5 patents. On the top of the column we find the proprietary Andros G2 stem developed by Tern. It provides ample of handlebar adjustment for an ideal fit no matter whether the rider measures 5’ or a lanky 6’5”. The telescopic seat post offers the same wide range of adjustment for the remaining contact points. Mounted on top of the strong 2014 alloy post is the Tern Porter saddle which employs the patented GripPad “underside” padding, allowing the rider to conveniently shoulder the bike by the saddle. This certainly comes in handy when carrying it up stairs. As you can see a lot of thought has been put into the BYB to make it as practical in everyday use.

In order to enhance personal mobility to its fullest, the BYB model series also received a number of innovative accessories. Tern created a system which comprises of various proprietary racks, bags, baskets, as well as lights, tools and other useful parts and fittings. This is a surprisingly sophisticated system, from which the aforementioned Metro Transit rack is standard equipment. It’s has a minimalist design with many features, such as the trolley wheels, allowing the bike to be pulled just like a suitcase. The rack is also a perfect mount for side panniers, which are guaranteed not to be in the way of the rider’s feet as on other small-wheel folding bikes on the market. Under the special rack we find a semi-integrated fender (mudguard) and there is also a chain guard called Hebie which does a perfect job at protecting your trousers from being soiled.

Concerning further accessories, the BYB shares the mounting system with the recently introduced Tern e-bike range (GSD, HSD). The Combo Mount not only allows for greater loading capacity, but offers a wider range of possibilities for mounting accessories. Finally the BYB has done away with the folding pedal, replacing it with a quick release system for the left side in order to make the folded package even smaller.


This review should relate not only tell reader how the BYB riders, but the experience the bike yields in everyday life. First I’ll start with the ride character. Just like the previous two Tern bike we tested [link to the review!!!], the BYB P8 has natural handling, in fact it’s the best of the three models when it comes to road manners. Possibly the longer extension of the Andros stem makes the difference, but it could be down to some tweaks in the frame geometry. Warts and all, the weight distribution on the BYB is as good as it can be, so the tight corners can be tackled with ease and confidence. This bike can turn on a dime! This comes especially handy for inner city riding, the type of application the BYB was essentially designed for. I thoroughly enjoyed riding the BYB in Budapest.

Most of the new technology developed for the BYB actually makes good sense, and I’m absolutely sure a lot of effort has gone into developing the new folding city bike platform. The Metro Transit is probably the best rear rack Tern has ever devised, integrating the trolley function with perfect placement of the side panniers. It’s asymmetrical to allow for smaller folded size, the rails run inside the rear triangle: this is engineering at its best! The locking mechanism at the rear hub is also a substantial improvement over the magnetic system on previous Tern bikes. It offers greater security, while opening the bike involves moving a lever, which is easier than trying to force the two halves apart. And the best of all, the “accordion” folding places the chain between the two folded sections, hence it has no chance of soiling your clothes while carrying the bike.

Being 6’4”, I welcome the new telescopic seat post on the BYB, although the previous Terns I’ve ridden also provided me with the necessary seat height. (This cannot be said of most folders I have tried!) In this case some spare tube was still tucked in the frame once my preferred 82cm BB axle to seat top extension was set. My only gripe was the extra step of opening and closing the second seat post QR mechanism, but it’s something I can put up with. There are also some additional details on the BYB which grew on me, like the cute but effective bell, one of the most comfortable handlebar grips I have ever tried, and the aforementioned Porter saddle which solves one of the nagging problems of bike transport: walking stairs.

Finally I must praise Tern for including the premium BioLogic „Joule 3” hub dynamo with integrated Tern Valo 2 front light (41 lux/150 lumens) paired with the Deluxe LED rear unit, all wired internally for a clean look. This as good as dynamo lighting gets and it’s always there when needed. Elegant, nice, practical: one would need to splash out quite a sum to get one retrofitted to the bike!

BYB lifestyle

Undoubtedly, the process of folding and unfolding the BYB takes longer compared to Tern bikes employing the tried and trusted N-Fold technology. This is simply down to the fact that there are a couple of extra hinges in the frame, the adjustable stem and the telescopic seat post, as well as the presence of a mechanical lock mechanism. The folding procedure can be practiced and perfected, but it’ll still be bit longer and more cumbersome than with the N-Fold. This is the price you pay for having a very compact packed size paired with 20” wheels. The larger wheel size pays dividends out on the road compared to a 16 or 17” alternative, and the whole BYB package offers so much more than a mini-folder. Personally I have no trouble accepting the tradeoff.

As it stands, the BYB can be packed down to a more than manageable size for transporting on trains and buses (my commute involves either one or the other), and the package can be trolleyed as well as being carried in hand. It’s also compatible with escalators. Likewise, once I pulled the BYB around in the supermarket, so I can see the point of having a basket installed on the front Combo Mount in which one could simply collect all the groceries.

The question I kept asking myself during my time with the BYB is whether it will ever replace the Link series in the Tern city lineup? It offers more advanced technology and the system build around it is quite impressive. The development of new accessories for the BYB platform is bound to speed up as more are sold and ridden on the streets of cities worldwide. Nevertheless, the Link series has some merits, one of which is the lower price point. So it’s unlikely that entry-level Link models – like the excellent A7 we have tested on these pages – will soon disappear from the Tern range. The standard folding system is quite convenient, and the resulting packed size suits a good proportion of users. On the other hand, I’d still recommend new buyers to opt for the BYB platform, as it shares a lot of technology with the Tern e-bikes, and future product developments are definitely heading in this direction.

The recommended retail price of the Tern BYB P8 is HUF 430,000. You can find out more about this Tern bike model by clicking on the following link (in Hungarian):


BYB bikes have a separate webpage on the Tern site (in Hungarian) here:


Hungarian distributor for Tern bikes: www.tern.hu.

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